Woah now! Anime is becoming the new comic book here . In a couple of years you’re going to see anime adapted movies and more. Anime is huge now and in some ways way better than anything America put out. Manga pretty much destroys the comic industry. So yea it makes sense for them to get anime stuff.
Now yes I will agree that a lot of it is very weird and cringe. Also very **** friendly BUT the stuff that is good is GOOD. Anime is peak fiction!
Part of mainstream "acceptance", IMHO, comes the vast success of modern video games.
For example, the game Dishonored has better writing than a lot of "prestige" level original programming TV shows out there. When you see that quality of writing and storytelling in a non live action format, it tends to normalize anything animated aimed at adults.
What I believe marked a large scale change is creative types figured out that hyper realistic animation isn't a selling point. It's the writing and story telling. Final Fantasy - The Spirits Within is a visually stunning film for it's time. It's also got major narrative and pacing problems. However a film like Ninja Scroll is just plain interesting action/paced storytelling.
Where I find that animation has a massive advantage is the format takes away a lot of the emotional charge out of many types of narratives. Stephen King has one story, The Long Walk, that has struggled to be adapted when literally everything else he's written has been turned into a film or TV series or mini series. TLW is just too controversial if it was done in live action. However if it was animated, it would take a much different tone. A good example is the old game Deus Ex. That game covered A LOT of topics that would have caused some real problems if it was live action. But since it was a video game, the tone and perception was simply different.
It's cheaper and faster to animate something than to get a big name live action movie star and start a huge big budget production. The cheaper it is, the more the showrunner and creators have some freedom in their storytelling.
MCU movies have to consider the way the script can be marketed and to further the entire franchise and create a practical level of cost certainty in the financial equation. They are often big budget affairs and thus need to hit a specific checklist instead of just focusing on a really good story. This is where animation, if done right, has an edge. The ability to turn a profit is different, thus the intense pressure to be a huge hit is different.
Imagine if someone wanted to tell the story of Schindler's List, and if no one had made it yet, but they had no budget and no chance to get big name actors and lots of marketing support. How do you get period era uniforms and locations and sets and an endless list of things to do live action. But if you animate it, your potential is almost unlimited.
That's the exciting thing about animated films and TV series that want to lean more towards "prestige" type production values aimed at an adult audience, it opens up doors to new talent and young upstarts who might have a lot of real creative vision.