Yes, gmail, calendar, youtube, etc. are slow and sometimes broken for weeks in various ways in FF.

Of course there likely won't ever be hard evidence that they are doing this deliberately. There are many ways for them to achieve this outcome without explicitly instructing their developers to degrade FF experience.

They can successfully bullshit most users that way, but for me this is just more reason to use FF more and Google less. I just hope there are enough other people with the same attitude for us to matter.