Generally, people credit Akira with bringing anime into the American mainstream, which would have been 1988, but by 1997, Princess Mononoke had a national release in theaters in the U.S., with Billy Bob Thornton doing a voice a year after Slingblade, i.e. when he was one of the biggest celebrity actors in the U.S. (Almost the whole cast was famous, which was really unusual at the time for animation.)
I was 20 when that came out and I don’t remember a lot of people saying that they wouldn’t go see that silly kid’s cartoon because it was very clear by then that anime wasn’t just for kids.
You still get people who think anime is “cartoons”, but they tend to be older.
I feel like around ~20 years ago is when anime started entering the mainstream.
Generally, people credit Akira with bringing anime into the American mainstream, which would have been 1988, but by 1997, Princess Mononoke had a national release in theaters in the U.S., with Billy Bob Thornton doing a voice a year after Slingblade, i.e. when he was one of the biggest celebrity actors in the U.S. (Almost the whole cast was famous, which was really unusual at the time for animation.)
I was 20 when that came out and I don’t remember a lot of people saying that they wouldn’t go see that silly kid’s cartoon because it was very clear by then that anime wasn’t just for kids.
So I would say closer to 30 years.