I think they would have seen this coming, they just couldn't do anything about it.

The rise of social media has moved most human generated content onto a few platforms, most of whom don't let Google index them (facebook being the main one).

They probably need to figure out how to pull information out of youtube (which there seem to be some initial efforts at).

However they might already be in trouble there, as TikTok is growing a huge archive of 20 second answers to common queries.

The websites are stuffed full of ads ... Google ads. Where's the incentive to change? They don't pay, their customers do.

They do make an effort. They're just losing the arms race.

I'd call most of them "saboteurs", not "competitors".

Google's market is ads. SEO "content"'s market is ads. They are definitely competing.