Well in terms of music its basically like saying 6ix9ine is better than Dre because he is younger by saying Marvel is better than Scorcese because it's more popular now.
I'm not sure what critics are saying Marvel films are better than the likes of Scorcese's classics unless it's marvel fans using multiple accounts to boost IMDB scores or whatever.
Maybe there are legitimate critics saying it I can't really say . I would find it hard to believe though
Well it's not saying that, if you see the argument that I'm making... Yes Takeshi exists in the current music landscape, just like Vanilla ice existed in the era of the chronic. And just as Dre existed back then, the likes of kendrick, cole etc exist now. The main thing is you have more of everything that you want. If you are a fan of old school style rappers with deep lyrical content they are a dime a dozen now on spotify etc and some are the biggest artists e.g. Kendrick. The same with movies.
With regards to Marvel movies, critics have praised gotg, infinity war, civil war, iron man, with black panther being the standout of them all in terms of critical response. Outside of Marvel you have the dark knight, batman begins, joker.
But the point is this, yes there are loads of superhero movies nowadays, just like there used to be loads of action movies, some of which were classics. But there are also loads of good indie films, and for example I think there are some really great creepy horror films being released in the past 4-5 years.
On another point, something that I do think contributes to a shift towards more blockbusters at the cinema and the rest to streaming sites is that most people have a mini cinema at home and for me at least ive watched some great films like moonlight for example with my girlfriend at home on a big screen and I could say it was probably better that way.