I disagree with your assertion "There's tons of areas where that AIs, or rather, basic ML, could be used". The issue with AIs or ML or any probabilistic prediction of what user wants is that it takes away control. E.g. sorting your apps by usage. It's a solution in search of a problem. If you rearrange my apps by usage, you are asking me to search my apps everytime. It breaks my patterns and habits. And we are animals for patterns.

There are some definite places where AI/ML/Adaptive algos help. Examples would be Facebook search, Apps recommendation, music recommendation, smart playlists, autocomplete and search etc. where any good tech team worth its salt is already using these techniques.

It's also the reason why Knowmail or Inbox by google are not great. I go through my mail in a set pattern. I code those patterns by labels or folders and clean folder by folder. I don't need to context switch between each mail of similar definitive categories. In these mail solutions, I make decision of the context on each mail. Is it a support email or a collegue email or a mail from my priority mailing list or from a developer for tech problem?

And that's why I'm thankful that AI is not being used in the tons of places that you refer. You will put me in a world where I'm living by someone else's patterns that mine own.

At the risk of generalizing (but reinforcing the patterns thinking), it's a common pattern with Engineers to apply a solution on all kinds of problems without challenging the efficacy of said solutions for those problems.