Right. Advertisers didn't bother with all these tactics because normal chrome users could download a plugin without any major hurdles to thwart it. Why drive people that wouldn't otherwise use an ad blocker to do so?
That's going away now. Now mostly everyone is vulnerable with the only recourse being pretty technical stuff, not just downloading a very popular plugin.
So advertisers will now be free to get more aggressive without much downside.
Edit: I do get that this sounds like conspiracy theory. But it really matches the Google boiling frogs approach. Removing the blocking onBeforeRequest, as one of the very first things in the manifest v3 spec was not a coincidence.