> I assume many of them stop working with MV3.
Most of them will not.
The only real limitation in m3 is the lack of blocking a network request on its way out to inspect it (you absolutely can block it - and the second time it's made you can block it after inspecting the first instance, but you can't inspect then block). To be clear - that's still a loss, but it's just not on the same scale as the type of loss that was originally worried about when Google first announced m3 without a way to update blocklists dynamically.
At the time - they were intending blocked URLs to be placed into the manifest file directly, which can't be updated without a full update to the extension in the webstores (2 to 3 days for chrome, couple of minutes for Firefox after first review).
That's a real pain, since you couldn't do something like heuristically determine that a request was serving an ad and then block it the next time it comes around.
But you can, now (and again - it's not as nice as it was, but it's still there).
There are still some limitations that are a pain to juggle (max size of the blocklist, max number of dynamic rules) that do make life a bit harder, but those I can genuinely see compelling reasons for adding - every comparison the browser is making against a blocklist for each outbound url is adding overhead on TTFB for the user - I think their caps are too low still, but at least I have a technically compelling reason to understand why the limitation was added (something other than - Google wants to unblock ads).
Basically - I'm telling you, as a subject matter expert in this space: Most users will not notice a difference. Some very discerning users, and some technical users might, but a lot of those folks are already off the Chrome train anyways.
> what I'm saying is that the advertisers might take action on all of them once the best option is hobbled. Then it's worth doing something that will break almost all the adblockers. One effort that puts everything to rest.
What? What power do you think advertisers have here that will suddenly undo the foundational hierarchy of the internet? DNS ad blockers literally aren't going anywhere anytime soon, and I agree with the general thrust of "If Google destroys ad blockers - users will leave", I just don't think they've done that with m3.