I can't say I've read all the comments om Patreon, but as a patron I usually scroll through them when there's a new post. And I gotta say, you need to be absurdly selective to conclude that Eva's "notorious for slow work progress" among them. She's getting almost exclusively positive feedback there, even on post where she excuses herself that the updates doesn't come out as quickly as she wants. Either you're just lying now to defend your own argument, or you've found one or two negative comments among hundreds of positive ones, and think that is the same as being "notorious" for something.
Someone posted a comment recently about how they had timed one playthrough, and I think it took them 22 hours. You're not anywhere near accessing all the content if you're just playing the game once, so with those 22 hours in mind, it wouldn't surprise me if it takes 50 hours to play all of the available content. Eva could easily make a game with less branching and fewer characters and illustrations per scene, and make a game that took 15–20 hours to play instead. In that case we're talking one game per year, which would be extraordinarly quick compared to other similar games. In other words: It's pretty meaningless to just look at the total development time and say that it's "a long freaking time" without acknowledging how big the game actually is.