Have you seen the state of AAA gaming and blockbusters lately? Even music is being utterly destroyed by the streaming platforms and record labels greed, so yeah it might have been in the 80s up until the 2010s, but enshitification got the best of the US I'm afraid so not even culture anymore. It's just decacence.

It's not all US, but as you said things start in the US and trickles down across the rest of the world, so that's also true for its decadence.

Nothing is really replacing this elsewhere though (although I do concede China is trying hard).

Lets start with movies: Most top grossing movies are still American based and centric. I was reminded of this recently when Obsession came out and I tried to get my German friends to watch it. They missed so many subtle 'Americanisms' in the movie that it really gave me a new perspective on how ingrained the culture is. 10 years ago living in Europe I was amazed at how much American music French people listen to and sing to. Even on random French shops its nothing but American music playing. I don't believe they suddenly switched to French music. (Is there some pop artist in France stealing the charts right now? Im curious to learn). And this is the country with Académie Française.

The Chinese are trying: Ne Zha 2 was quite nicely animated and it grossed an impressive amount but that seemed more like a one trick pony given that it really attracted massive Chinese audiences and they seem to know how important the film was. This is just an opinion but it was not a memorable film like I'd expect from a Disney classic.

Then there is food: Its fascinating how Luckin had its massive comeback and has forced Starbucks to retreat in China and other markets. Mixue might do something similar to chains like DQ and Baksin Robbins, (lets see what happens). I have yet to see the Chinese Mcdonalds but maybe its in the shadows waiting for the right moment like a lot of Chinese companies.

In terms of Gaming, it still seems like despite all the BS, the market is still treating Western game publishers as the gold standard (and mainly American ones at that). The market dynamics are different for Gaming vs others because gaming is so diverse. Maybe there isnt really a leader given the ease of competition. Same goes for music. Streaming seems like what the market wanted or else they would have stuck with physical media.

I don't think they're merely referring to media/arts as culture.

Enshittification is culture too, and it's certainly spreading.