Manifest V2 functionality that has been cut out was used only in adblockers, right?

And we have adblockers built-in in various browsers now.

So since we have built-in adblockers, we don't really need MV2 functionality anymore? Why oppose MV3?

I mean why people want to oppose MV3 instead of simply asking your favorite browser to expose the browser-specific API for missing functionality, like it was done "in the old days"?

If Google wants to block MV3, then let it block it, and ask browsers to expose missing API. Of course this won't happen in Chrome, but back in my days when software was limited, we simply stopped using it in favor of more complete software.