Personally, I feel like Americana-inspired fantasy is a huge wide-open sub-genre right now.
I think you're right, but I have little interest in writing fantasy set in something inspired the colonial period, or the old west, or the gold rush or other US history inspired times. I kind of like the whole swords and sorcery, quasi-classical era, and early gunpowder-era vibe.
Also, I struggle with how to write something that has an early Americana feel without addressing the issues of colonialism and the treatment of Native Americans (I don't want to just pretend they don't exist). One fantasy book I can think of that kind of tried to do this is a secondary world was Robin Hobb's
Soldier's Son trilogy. There were some things I really liked about this, but the way she portrayed one of the native cultures (it felt kind of like an "all plains Indians stand in") bugged me. I'm not sure what her inspiration for the Speck culture was, or if it was more or less made up from scratch, but it felt a bit clumsy too. The most interesting part of the story for me was Nevarre's relationship with his father, cousin, his best friend, and the woman he met later on, and those could have taken place in any setting. But imo, Hobb's strength always was in writing relationships in her other books too.
But beyond that, why do things always need to be inspired by real-world cultures? Seriously, fuck that. It's boring. It's copy-cat. Forget it.
Come up with something truly fucking original. Not just a re-hash of some world culture.
That's sort of my thinking too, though I know my sense of general aesthetics is still very influenced by architecture, clothing and other trappings of certain times and places, even if I change a lot of things about the cultures and history of my world. I have a novel set in a sort of early gunpowder technology level, though with quite a few changes (it's a matriarchy, for instance, and of course there's magic, and a religion that's not, as far as I know, like any particular real world one).
But I keep going back and forth on how people should dress. Since women have a great deal of social freedom and mobility compared to the real early modern era, it's silly to think they'd be burdened with the kinds of clothes women were required to wear at a similar time in our world, but do I want men and women to dress exactly the same? That seems unlikely too. And what if men are the "pretty" ones in this world? That makes sense if women control most of the wealth and men have to prove their value to join a wealthy, female-centered clan when they marry. They'd be strutting around like peacocks.
But could most readers get into a story with a male main character who is more worried about his hair getting mussed than the female one is?
Then I start thinking about architecture and think winder why they should be living in houses that look like ones from England at that time, aside from obvious constraints of climate (it's kind of like the pacific northwest climate wise). Same for foods and other such things. Why can't they have turkey, yams and rice? No reason they have to come from different continents in this world.
But certain kinds of things are comfort food to me. Not boring. To be honest, brilliantly original fantasy like
Updraft (with its emphasis on flight and living towers of bone) are something I admire, but not my go-to preference. And I prefer to imagine my characters in settings that are more ... comfortable, or at least a bit more familiar (since I also like to make them pretty miserable). I think it's because when I visit historical places, I really enjoy trying to imagine what it would feel like to live in a house or town like those and then I start to make up stories that twist things but retain a basic aesthetic.