I would have assumed the same, but given that I doubt Jerry is in any financial straights, I don’t think that’s the case. For some of these stars, they can make a lot of dough for some of these private gigs, in the low millions, so why not strike while the iron is hot? Jennifer Lopez was paid $1.25 million dollars to play a birthday concert for a wealthy Chinese family way back in 2014. Celine Dion, Beyonce, and a slew of others have done corporate gigs.
I read the article, which reminded me of the opening scene from the HBO series Silicon Valley, which shows Kid Rock performing his heart out, to an audience of a couple dozen geeks who seem bored by the whole thing.
(And the low-rent version of this sort of thing might be Cameo, a website that allows you to hire a lesser celebrity to record a video greeting for a friend or family member, for a few hundred dollars.)
For a minute there, I thought you were referring to the funk band Cameo and thought they were singing “Word Up” at corporate events.
ISTR reading an article 20 years ago or so about some entertainment industry big-shot booking Don Henley and Joe Walsh for his daughter’s bat mitzvah. I believe they got a couple million each to hang out and do a little jam session with the guest of honor.
Damn, the biggest musical act we ever got was someone called Big Bad Voodoo Daddy.
Also, we had some time with the guy who replaced Miranda playing Hamilton before seeing the play, and we also spent time as sponsors at the Utah Olympic Park with speedskater Dan Jansen.
Woo hoo! 
My gf was doing some advertising work for Smokey Robinson’s Winery. She had a meeting with him, and casually mentioned that the agency had a Friday Happy Hour. She asked if he wanted to grab a drink/snacks and he shocked her by saying yes.
I did remember one that I guess qualifies. We received an offer in the mail from the Borgota (casino in Atlantic City). Since we had been a customer the Old Homestead (NYC steakhouse that opened an additional location in AC) we were invited to their 10 year anniversary celebration. We had gone there once at that point. I looked this over and said to my (now ex) wife, “There’s no mention of price. I think it’s free.” She told me to call and make sure. Yep it was free. So we booked a room and went down on the date.
It wasn’t in the restaurant it was in the big ballroom. They had four carving stations with prime rib and lots of other food. All free. All you could eat. I could eat a lot.
The head of the casino grabbed a mic and thanked us for being there. Then he brought out the surprise guest as the MC, Steve Schrippa from The Sopranos. There were a bunch of very nice door prizes that we did not win but afterwards I met Steve Schrippa.
ETA this was before the final season of The Sopranos so it was still a big deal.
If you want to hear a funny story about a comic playing a private gig look up Jim Jefferies and Mariah Carey. I’m not linking because I’m not sure which uploads on YouTube are legit and not against copyright
Similarly, check out Gabriel Iglesias’s Fluffy Visits the Middle East.
Or Russell Peters doing the same.