I can think of a few grocery stores here that have "Katsu Curry" at the to-go section - definitely not the finest example of the art, but still pretty good. It has been pretty popular in San Francisco for a long time. Although, the post-pandemic era, I've definitely noticed a large uptick in places that serve it. I can think of a few reasons why that is, due to SF's history and culture. I have very fond memories of my last job circa 2015 or so: waiting in line for Muraccis on Kearny.
It doesn't seem anything like what's going on in the UK at the moment, though. I hope that larger trend takes hold here, it really is one of my favorite comfort foods. Golden Curry is a staple in my home.
Also, I've not often seen it called Katsu Curry in the US. That is definitely a name that would be considered accurate, but more common I've heard might be "Japanese Curry" (an important distinction) or "curry rice". It is definitely the same food, though.