I saw the astroturfing as early as 2016. It blows my mind that people aren't more outspoken about the threat.

I even see people defend it "you really think a trillion dollar company is going to be advertising here?"

Yes duh? They are called reputation management companies, and they are contracted for plausible deniability.

I've seen it play out like this- a few well placed top level comments that defend a companies actions. Those are upvoted, anything contrary are downvoted.

You can see this when a thread is massively upvoted to a front page, that's something that a company can't really control. They don't have enough voting power. However inside the thread, people won't spend as much time upvoting and downvoting comments. This is where voting rings make the difference, controlling the narrative in the comments.

The companies with rabid fanbases are those that benefit most. If they can control the narrative, the fans will take the bait and run with it.