There was a long period of the where IE was far from dominant, but was used in enough places that supporting it was non-optional for many businesses. It was holding the web back.

I think it's that period of IE that people are referring to when they say Safari is the new IE.

Which is hilarious as that period was only possible due to the previous embrace-extend-extinguish period that preceded it. Which is the state Chrome is in now.

Perhaps, but I think Google still has a much stronger incentive than Apple (or Microsoft) for the web to be a viable platform. I don't think they would allow Chrome to languish the same way IE did. Instead it's more subtle moves like nerfing ad blockers.

Google has been nerfing the entire web and their search engine for many years. The AI slop flood is their doing in many layers.