Dont you think it's more because Chrome is backed by a trillion dollar company and it's kinda the go-to browser nowadays because everybody believes Chrome is faster than Firefox? I have a bunch of friends using Chrome, but they all say it's for speed, not for switching profiles?
And I have a bunch of friends that say it's because it lacks the profile functionality and they can tolerate the speed.
It's not the only issue Firefox has, but it's the highest impact, lowest effort one they have. Performance improvements are hard, PWA is hard to implement. Putting a better UI on existing functionality is simple by comparison. They could score an easy win here, but they choose not to.
