At this point, I think it's almost mainstream, and it's still growing fast (and it's getting better, rust-analyzer is really awesome these days, I was there at the beginning, no comparison to today…))

I may be biased, but I think it'll be the next big main language probably leaving other very popular ones behind it in the coming decade (Entry barrier and ease of use got much better over the last couple years, and the future sounds exciting with stuff like this)