He means "if it actually happens/my shit stops working one day" he will switch.

We've been listening to this shit for like 2 years between Manifest V3 and this, I've never had a single difference in ads that entire time on Vivaldi.

It's got baked in features that run lighter than what Firefox would be with the equivalent extensions and plugins, if it stops working then I'll switch. Running Firefox isn't going to stop this from happening, if and when. Only massive user backlash after implementation will solve the issue, same as when Lemmy was created.