It could be argued that Joan Rivers currently has a nighttime talk show on the air with Fashion Police. Granted everyone talks about a single topic, but they have that audience, they have give and take and a single person sits and controls what happens.
I have always wondered about the lack of a female second banana.
Didn’t Paula Poundstone briefly have a late-night show, or did I hallucinate that?
It looks line we have no consensus as to why we observe what we observe.
Yes, there was Joan Rivers in the 80’s and apparently Paula Poundstone, Stephanie Miller, and Wanda Sykes had short-lived late-night shows, and Chelsea Handler seems to have a show.
But, that doesn’t change the basic thrust of the OP, which is that the field is completely dominated by men, by any meaningful sense of the word ‘dominate’.
We got some theories from marshmallow, **BigT **and Lamia, but it doesn’t seem that we have a consensus as to what is causing this.
She had a variety show on ABC, which according to Wikipedia lasted only two episodes, but I remember seeing one of those two episodes and I’m pretty sure it was in primetime and not late night.
It’s not just at the top. The feeders for this kind of comedy (improv) are male dominated, from Groundlings to SNL to Whose Line to stand-up comedy. Maybe even to the college level. Like other male-dominated industries, it’s institutionalized and it will be probably another generation before enough women can come up through the ranks and reach critical mass.
I would say it’s also not work women seek out as much as men. Wanting to go into comedy as a career requires sacrifice, and wanting to go into a male dominated field where you might not be respected is discouraging.
My cite is Bossypants, which discusses institutionalized, “normalized” masculinity.
I have a feeling it will change when the writing staff of shows like this change from having a “token” woman to closer to 30-40% women.
Daily Show - 25%
Colbert- one token female
Those are the only shows with easy lists, but watch the writing presentations at the Emmys.
Women who might have been successful late night hosts, like Rosie O’Donnell and Ellen DeGeneres, found success in daytime instead. Not as risky, as Bellhorn said. Black comedian hosts have been relegated there as well.
I guess the “why” is just “it happened that way over the last 65 years.” Like presidents and celebrity chefs.
Sure, but most late night hosts come from the comedy circuit or an improv group or similar, an arena which has few successful women. I haven’t followed standup in years but I could name a couple popular current male acts. Women? I have no idea. Is Sarah Silverman still a big deal?
Anonymous ratings and memory.
Women in the boardroom.
As for women speakers, I couldn’t find the one I remember. This is in the ballpark, but it’s just some neurologists observations for a book about face to face interactions. I recall one about speakers in front of test audiences. Sorry.
I’m betting unwillingness to screw with the formula too much is part of it, especially on the big three networks. Announcer introduces the show with band playing, host does opening monologue, sit down at a desk, do a bit, go to commercial with the band playing, come back with the band playing, call out the first guest (who sits next to the host’s desk on the right, almost never the left), do another bit, musical guest, another guest, another bit and/or standup comedian, run out of time for Matt Damon, band plays as the host says goodnight, credits. The host is a guy because Johnny Carson was a guy, and the major networks assume that’s what people want to see.
What I find funny about that is that the networks seem not to understand what makes a talk show host successful. There have been a few very successful late night hosts, and many flops. Given this, I’d think they’d be willing to try something different.
I’ve been trying to pin this down in my mind, and something about a male comedian is just more real and believable. When I see Sarah Silverman do standup, it seems like she’s trying too hard. Whereas the same jokes delivered by Louis CK would be laugh-out-loud funny. I guess I’m sexist.
I’m not sure there is any one reason, but late night TV on networks seems to be very conservative, and when a show succeeds, the host stays forever: Carson had the Tonight Show for 30 years, Letterman has been going even longer on his shows, Leno and Conan have been around for 20-plus years on different shows, Jon Stewart (on cable) has been on the Daily Show for about 15 years, 10 years for Jimmy Kimmel, and Colbert (also on cable) and Ferguson have had their shows for about eight years. So with that slow rate of change you might expect the shows to be behind the times that way. People want something different but not too different. The influence of producers probably shouldn’t be discounted either: if you’ve had one successful late night show you’re more likely to get a chance at producing another, and Lorne Michaels has now put Conan, Fallon and Meyers on talk shows. Letterman also produces Ferguson’s show and Jon Stewart produces The Colbert Report. So if you have these decisions being made by a small number of people and they try to go with what worked before, that may explain some of it. Bill Maher has also been hosting for a long time. Good news for John Oliver, I guess. If he lasts a year or two he could have an HBO show for decades!
I love her show - wish it was a full hour!
I’ve been trying to come up with a “has to keep it short because Chuy” joke for the last five minutes. I give up. 
Actually, the reason they gave Rivers her own show was that she was a successful Guest Host on the Tonight Show during its Johnny Carson era – arguably the most successful of the Guest Hosts*. Carson felt betrayed when she left to start her own talk show, and the demise of her show might owe a lot to the infighting and sabotaging capabilities of talk show hosts as to Rivers’ innate talent. Don’t judge Rivers by her current Red Carpet gigs and books – she was seriously funny back then.
*Back in Carson’s day, he would often leave for extended periods of time and designated guest hosts would take over. I haven’t seen anyone else do this until Jon Stewart left to do a film and John Oliver took over his spot recently.
Late night talk shows? Hardly any in the UK, ever. Mind you, we only have three mainstream late night shows at the moment, and two of those are hosted by flamboyantly gay and out men (Alan Carr and Graham Norton). Not sure what that says about us.
Comedian Sarah Millican did a short run recently of late night chat shows. Not sure what her ratings were like.
I remember seeing Joan’s last appearance on Carson. She wasn’t hosting, just a guest. She and Johnny strolled down memory lane. She mentioned the dress she was wearing that night was the same dress she had worn on her first appearance on The Tonight Show. It was all sweetness and butterflies. The next day they announced she had her own show on Fox. So yeah, Johnny felt like he was stabbed in the back.
Add in she was on a fledgling network (Fox at that time) and her show was in the same time slot as Carson. Rivers and her husband/manager didn’t realize that while people enjoyed watching her sub for Carson, they weren’t tuning in to see her, they were tuning in to watch The Tonight Show. Oh, and potential guests didn’t want to risk being perceived as taking sides against Johnny by appearing on Rivers’ show.
Back in those days, one might turn on the Tonight Show, and dread hearing Ed McMahon say, “Tonight’s special guest host is John Davidson.” 
It seems to have escaped everyone’s notice, but late night over-the-air comedy hosts are also overwhelmingly white.
TDS has a half-female lineup of “correspondents”, though. Now that John Oliver is gone I can see them pushing Jessica Williams as a potential future host, which would kill two diversity birds with one stone (and would be awesome, 'cause she’s hilarious.)
Looking over the list of former TDS correspondents reminds me how much I miss Vance DeGeneres.
That would be terrible. She has one note… “White People Be Racists!” It’s funny (OK, really funny), but I don’t see her as a host.
That’s most of what she does on TDS but she’s done a bunch of non-race bits and they’re far better.
“The version I heard was,”
(a) Rivers felt that Carson slighted her first when she discovered a “leaked” memo with the short list of who Carson wanted to replace him when he retired, and her name wasn’t on it;
(b) supposedly, the reason she didn’t mention it to anybody, including Carson, was along of the lines that it wasn’t a done deal until it was announced;
(c) Carson made it clear that anybody who went on her show would never be allowed on his, so few people who made appearances shilling their latest movies/TV series would have anything to do with her show - after all, The Tonight Show is The Tonight Show.
Then again, there’s (d) the fact that the show was on at 11 PM Eastern/Pacific, which is when most people who are up that late watch their local news. True, the Fox affiliates had 10 PM local news programs, but this was not really an option to anyone who had a favorite 10 PM network show (examples at the time: Cagney & Lacey; Hill Street Blues; L.A. Law).