This was the new interface, right? I just saw this the other day and though it looked pretty good; was actually considering a trial switch back (after moving to chrome years ago, when a single bad tab would take down the entire browser).
That’s now put on hold - a compulsory extension is one thing, but having it be purely for advertising is a massive “No” flag to me.
I’m of the view that getting (most) people to consider switching browsers only comes every few years and requires a very large incentive; “We’ve fixed that one incremental problem” isn’t enough. A complete revamp would do it, but takes time to permeate into conciousness. And in the meantime they do this. “Squandered goodwill” seems to be spot-on.