1) actually-necessary design work on a product is very boom-and-bust. 2) for years now, tech companies have hired enough designers for the boom periods, rather

1) actually-necessary design work on a product is very boom-and-bust. 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.