IMHO, most adults go for anime like fantasy stories, that would be hard to do as a live action show without tons of CGI. Idol type shows don't fall into that category can easily be done as a live action without CGI.

This is a closed minded false narrative by someone that has done zero research born in an era where parents basically shut American animation capabilities which is why for a long time there were nothing but very childish children's shows. Doubt me. Well Find the dated 1980s American/Canadian movie called Heavy Metal and you will see what kind of things we could be released. Most cartoons in general were also based toward older teens and more adult oriented too. In the 90s and 2000s parents started suing media companies because they didnt like what their kids were watching so the laws of what could be releases (especially with anything animated) got really strict. It wasnt until streaming services that the laws started to become more la again in the U.S. at least. Cant speak for elsewhere.
Its not that the Japanese are just better.  They are just more liberal with media. The fact that the U.S. destroys every other country with overall quality of movies and overall worldwide income made with movies proves we have the capability.

Strict laws can hamper media in any country