These are all symptoms of a larger problem: very few people care about the users, and you have instead classes of workers living in a bubble, working towards either micro-optimizing metrics or trying to achieve what in their minds is the "ideal" product, pushing the latest fashions of their branch.

So UX engineers will unleash the latest fad (see Apple's glass UI, or Material Design, variations of flat gray design, etc...), PMs will insist in dumbing down UIs, engineers will push whatever micro-service architecture because it's "cool" or push for rewrites in Rust / Typescript. At the same time, it's very rare for companies to have a single person (or restricted group of people) with a global view on what the product line is trying to achieve long-term.