2) for years now, tech companies have hired enough designers for the boom periods, rather than contracting or just dealing with longer design cycles—I suspect this is Apple's influence leading to much larger design budgets and resultant empire-building.
3) bust-period design work doesn't get one promotions or look as impressive in a portfolio as boom-period design work, so design departments or individuals are heavily incentivized to create artificial "booms" both so they have enough work to do and so that the work is helping everyone advance their career. These align well with product manager career advancement incentives (everyone loves screen shots) so they get green-lit. These are the unnecessary and often ill-advised redesigns that we see so often.
https://9to5google.com/2018/07/17/google-blob-emoji-gboard-s...
My educated guess is that someone working in a private company has to justify their salary, even when there is nothing to do. So they come up with "absolutely necessary work to do" by inventing themselves solutions and "improvements" for problems nobody has.
Now we have a team of +10 people doing meetings, colorful charts, analysis, etc. Including writing blog posts like "changing the world and fighting a pandemic by changing the size of the tabs". Bosses raise the head and see all the cubicles busy. Everybody is happy.
Now that it's released it's time to think about the changes for the next version.
PS: I'm a happy Firefox user since it was just "mozilla".