Until google announces that adblocks will be blanket removed from chromium as well. The truth is the only company big enough to maintain a fork this different, is Microsoft, the question is will they feel like they should, or will they side with Google, since this is by their interests as well..
There were people back in the day who thought that the internet was that fancy E on the desktop (internet explorer) and would have their brains melt when trying to explain alternatives. I think that people now have this problem with a fancy G.
And thus, entropy is presented. Even if only 10% go to Firefox, thats still 10% that aren't going back to Chrome. And if this repeats with similar results, as you imply, that 90% going back to Chrome is gonna be a lot smaller a few iterations from now.
Until they use their multiple monopolies to further cripple the experience for competitors, entrenching their dominance, and allowing them to force their proprietary standards on the internet, killing any remaining pretence of Internet freedom.