My guess is that it involves a different balance in the battle of the sexes side of the characters. In the "typical" Romance, the woman has most (all?) of the power (in the relationship, not in the world at large), and the plot is a long unwinding of the man coming to accept his new submission.
The theory of the English novel (and in effect the American novel as well since the American literary scene was so dependent on the British literary scene until the Civil War) holds that the first true novelists, in the sense that we understand them now, are Samuel Richardson and Daniel Defoe. Both were Puritans interested in defining morals and mores through novels.
Samuel Richardson's most famous novels, Clarissa and Pamela, involved the seduction of women by men. In Clarissa, the main character is actually abducted. Despite subcumbing sexually to the rake, she retains her virtue due to her spiritual and moral superiority. Granted, this is definitely not the stuff of romance these days...but it was plenty titillating for 18th century England.
Romance is partly about gender and the differences in power between the two. But more often, it's a device to examine social situations, to examine the shifts of power due to money, status, and even politics. In my opinion, I think Henry James is the best novelist to ever use marriage as a plot device through which to examine society, particularly the difference between American and European societies. While scholars like to examine his language and technical skills, what seems less discussed is how weird and scandalous his plots are. Here are some examples:
Wings of the Dove: A penniless British girl prods her poor beau to pimp himself out to a dying rich American girl in Venice.
Golden Bowl: Rich girl marries penniless Italian aristocrat, a prince. Rich girl's father marries rich girl's best friend, who is also penniless. Unbeknownest to rich girl and rich father is that the girl's best friend and italian aristocrat are having an affair. What is even weirder is an undertone that the couple having the affair think it's okay because the rich girl and rich father are so overly affectionate of each other that it verges on incest.
Which is why romance writers will continue to be mocked, no matter whether they can write well or not
The typical romance now is a formula. I once saw a Harlequin chart that they give out to booksellers that grids out the market based on demographics, age, income and a few other variables. As the bookseller who showed this to me said, it's amazing how well it works and how they really do have books written exactly to these specifications.
However, it's good to remember that our novels started off with some scandalous romances and some adventure stories. As much as I love literary novels where nothing happens, I also am glad that writers like Kazuo Ishiguro and Peter Carey are experimenting with genres like the detective novel (Ishiguro's When We Were Orphans), the western (Carey's novel on the Kelly gang), and sci fi (Ishiguro's Don't Let me Go). It puts a lot of zing and fun back into literary novels that have gone a little stale with existential angst.
Yeah, when you think about Henry James' books, the whole veneer of his language contrasts wildly with the action and plots. Turn Of The Screw still has students shaking their heads in bewilderment-- at least those who paid attention. And wasn't there a story about a man who adopts a preteen girl with the goal of raising her to be his wife? Creepy.
The typical romance now is a formula
Well, yes and no. The monthlies are certainly formulaic, and publishing "phrase books" to help beginning writers get published doesn't help this perception any. But man, the variety in the field once you get past the entry level work is amazing: pregnancy and babies, office romance, police procedurals, time travel, old west settings, modern west settings, international, paranormal, Regency (both chaste and not), sports (including Nascar!), espionage . . at least when it comes to the background and setting, it really doesn't seem as if there's a typical romance any more. YMMV, but the genre has certainly evolved a lot since the mid 80s, or even the mid 90s.
As far as writing to a formula goes, it's hardly a problem for romances alone. Serial westerns are just as bad, perhaps even worse, because the reader expectations are even narrower. And the action adventure genre! Mack Bolan is the most successful brand name (check out that author list), but from what I've shelved, the genre has not been plagued with excessive ingenuity. And mysteries? A little more variety, but still it too often breaks down into cozies, espionage, police procedural, detective and courtroom. Apparently readers know what they want, and will reward writers and publishers willing to give it to them :)
Ex ignorantia ad sapientiam; e luce ad tenebras
I'm not a big fan of mystery, but I really do enjoy the Marcus Didius Falco books by Lindsey Davis. Fun to read and apparently very well researched.
I can't argue with your logic...but I can recommend a good therapist