Wasn't this just microsoft back in the day that enabled it by default, and they were already a small player at that point (Chrome was the leader and even Firefox had more market-share back then iirc).

In other words: "browsers" didn't make it the default, one small browser did.

And so if _any_ browser, whatever tiny percentage they might have of the market, will make this new proposal the default, advertisers can again say "see? totally unreasonable, we won't follow that".

But it being made default by Microsoft was never the problem, ad-companies just didn't care.