You seem to be accepting the premise of the OP that there are lots of Jewish romantic comedies, where many of us are having a hard time thinking of more than a handful.
Would you or Colophon care to provide more examples of all these Jewish romcoms?
My impression is that Jewish characters tend to be overrepresented in film and television in general, and my post was a partial explanation for that. I don’t know that it’s specifically true of romcoms. Actually, I don’t know that it’s true at all. I have the impression that it is, though.
My two cents here is that although we may only be thinking of a a handfull of “Jewish” Romantic Comedies: Annie Hall, Manhattan, When Harry Met Sally, etc., the ones that come to mind are both very, very memorable and have influenced other movies in the genre.
I think that with several decades of output from Woody Allen and Neil Simon, in particular, to look back on, as well as the general comedy contributions by Mel Brooks, the Reiners, etc. certainly a great many light and/or romantic comedies have Jewish undercurrents whether or not the characters are overtly Jewish.
I decided to be really thorough about testing the claim of the OP. I took the list linked to in post #3 of the highest-grossing romantic comedies since 1978. I went through the first 40 on that list. I decided to eliminate three of them since I didn’t want to confuse my understanding by worrying about non-American movies. I eliminated number 8 on the list also because the male lead is not romantically interested in the female lead. They end up romantically linked with different people. I’ve listed below what the ethnic origin of the hero(ine) and love interest of each of those movies are (numbering the same as in the list linked to in post #3):
Greek heroine, WASP love interest
WASP hero, WASP love interest
Black hero, Hispanic love interest
WASP heroine, WASP love interest
Jewish hero, WASP love interest
WASP hero, WASP heroine
WASP hero, WASP love interest
Hero not interested in main female character
Black hero, Black love interest
WASP heroine, WASP love interest
WASP heroine, WASP love interest, anti-romantic comedy
WASP hero, WASP love interest
WASP hero, WASP love interest
WASP hero, WASP love interest
Jewish hero, WASP love interest
Eastern European hero, WASP love interest
Not American
WASP hero, WASP love interest
WASP heroine, WASP love interest
Not American, anti-romantic comedy
Black hero, Black love interest
WASP hero, Italian heroine
Hispanic heroine, WASP love interest
WASP hero, WASP love interest
WASP heroine, WASP love interest
Jewish hero, WASP heroine
WASP heroine, WASP love interest
Jewish hero, WASP love interest
Eastern European heroine, WASP love interest
Italian heroine, Italian love interest
WASP hero, WASP love interest
WASP heroine, WASP love interest
WASP hero, WASP love interest
Not American
WASP hero, WASP love interest
WASP hero, WASP love interest
WASP hero, WASP love interest
Black hero, Black love interest
WASP hero, WASP love interest
WASP hero, WASP love interest
I’m using WASP here as shorthand. What I really mean is something vaguely Northern European. The ethnic ancestry might not be British actually. It might be Irish, German, Swedish, or whatever, but it’s not Jewish, black, Hispanic, Greek, Italian, or Eastern European (and I don’t really know or care about their religious background). I’m going by what the character is supposed to be, not the actor. There are several clear cases on this list of a Jewish actor playing a WASP character.
There are several things to be noted here. I would have assumed that the main character would nearly always be male. In fact, ten of these 36 films have a female lead. It’s also interesting that most of these films have both a WASP main character and a WASP love interest. In the cases where the ethnic ancestry of the two differs, it’s nearly always a main character with a more exotic ethnic ancestry falling in love with a less exotic love interest. Romantic comedies are wish-fulfillment fantasies, and (yes, I’m sorry to say this, but it’s true) in American wish fulfillments the person is frequently trying to find someone with a less exotic ancestry. There may be a few romantic comedies out there with a WASP hero or heroine falling in love with a black or Jewish or Italian person, but such films aren’t the most popular ones.
I’ve flagged a couple of these films as anti-romantic comedies. This is a special category that I’ve noticed. (It’s not a perfect name, but it’s all I can come up with.) In these films, the main character and his or her love interest do not end up together at the end, even though otherwise the film fits the form of a romantic comedy. Because this list only goes back to 1978, it doesn’t include two of the best examples of anti-romantic comedies, Woody Allen’s Annie Hall and Play It Again, Sam. There aren’t really very many actors who followed Allen’s lead in playing Jewish lead characters in romantic comedies. Ben Stiller always does (although he is actually only half-Jewish by ancestry). Billy Crystal and Adam Sandler often do.