So we would have two levels of alternate history: the "good" (publishing-backed, very dense, very focused on "counting rivets" and generally as interesting as trying to read an instruction manual) and the "bad". (The things people try to do on Wattpad that will only have in common with the alternate history we know and love a vague aesthetic similarity.)
With my publisher's hat on: No.
Professionally published alternate history is designed to turn a profit, which means appealing to a mass audience. That means such things as story, plot, themes, characters, and so on are crucial, and no-one buying in the mass market gives a damn whether the STG-300D has 78 or 84 blades. Or how much saltpetre the Union imported during the ACW.
The river-counting is entirely for the obsessives in the audience, who make up a tiny proportion of the market.
Evidence: the back stories for things like The Man In The High Castle and Fatherland are, to put it mildly, unconvincing. That doesn't matter; they aren't about the back story except to give a bit of armwaving to justify the story in the forefront. They have done quite well on the market.
Publishers want to make a profit. That means selling books people want to buy. That means avoiding being "as interesting as trying to read an instruction manual", because that won't sell in the numbers needed to turn that profit.
AH existed before AH.com. It even existed before soc.history.what-if. Churchill wrote his famous DBWI on Lee and the Battle of Gettysburg; L Sprague de Camp wrote about a time traveller created a new history in Lest Darkness Fall, but he was drawing on Twain's Connecticut Yankee.
The big difference is that publishing houses have certain quality requirements of a story, and something like AH.com doesn't have those quality requirements. I've read good timelines here (and elsewhere), and bad timelines. I've read good timelines that are unpublishable for various reasons (length, lack of a story, among other reasons), and I've read bad timelines that have some good writing in them. I've also read bad timelines that are also badly written and incoherent, but I tend not to dwell on them (unless I'm being paid to read them).
The impact AH.com had had on the publishing community is, to be blunt, extremely modest. That's inevitable, because AH.com isn't a publishing house, and doesn't generate anything (apart from self-published works) that reaches beyond it's own community.