I don't know what region you visited, but in my area there are several different types of Asian cuisine available, with Indian being my favorite among the bunch. In fact, two of my favorite Indian places are right across the street from each other.
If you're looking for ethnic food at that level of proliferation in the US, it would have to be Chinese, Mexican or Italian depending on the region. There are also areas where Indian restaurants are more common than in others, like Redondo Beach.
I love Indian food. Samosas, lamb korma, butter chicken, and rogan josh - yummmm. Indian buffets used to be hugely popular (before covid). I miss those a lot. They have great vegan/vegetarian dishes too.
Another reason why some ethnic foods work well in other countries is because those ethnic dishes are changed to suit the palettes of the host country.
In Germany there is a dish called CurryWurst which is a sausage in tomato sauce with curry. Basically very German with the addition of the curry.
In England you have Chicken Tikka Masala which again is more suited to English palettes and was even invented in England.
Not sure if Indian's do the same in America but that might help them.
On a related note, is Fish and Chips big or even a thing in America? Very popular in Australia and Anglo countries I seldom see it mentioned in America.
Fish and chips are on American menus. I see it offered at seafood restaurants and Applebees type restaurants as an option. Unlike the UK, fish n chip take outs are not very common though there was one near me run by a British ex-pat family. I think they retired it a few yeaes ago.
There are a lot of Indian restaurants in the US. As another poster put it they tend to be where the Indian populations are. Here in NJ there are three within a 2 mile radius of me. There's even one in a food court in one of the local malls.
I also think that it's just weird to say that you don't like Indian food, or whatever type of food. There are different regions in India which have different types food, just like many other countries, and they are quite different. It's fine not to like curries, but that's hardly all Indian food is. How much of the Indian ( or Chinese, or Japanese, or Cajun, or Mexican, or insert random country or cuisine here) food that you've ( and I mean the collective you, not any individual in particular) eaten, is authentic and not tweeked to appeal to the pallet of your country, like the US or the UK or wherever?
There are flavours and some foods that I don't care for, and I have been accused of being picky, but I have never experienced not being able to find something that I can eat on any menu.
I would be happy to try some authentic Indian food that isn't curry, but when going to an Indian restaurant it's really hard to get past that curry smell which IMO, permeates everything.
I cruise frequently, (or at least did until covid struck), and because much of the crew is from Indonesia they serve very authentic dishes. I know that isn't Indian, but they do share many similarities and I have never had anything I liked and honestly, I will try anything once so I do have an open mind.
Curry in India really just means the gravy. Curry spice mix, from what I understand, is an English invention. That could be incorrect and I'm not fact checking myself here. Northern India uses Garam Masala. A lot of the "Indian" food we get is more of a hybrid of English Indian.
I guess if you didn't like any of the Indonesian food, I would maybe see what they had in common. Perhaps an herb, or spice, or flavouring that was in all of the dishes you tried. That's just me though. I will try anything as well, and have come across a lot that I don't like, but I've never been able to say that I don't like an entire nation's cuisine.