You're basically ignoring the past 30+ years of the gaming and cheating industry. Everybody already does log behaviour, try to find outliers, and have some systems to try to keep cheaters outside from the general player pool. That's what gaming companies have been doing since at least the early Halo days. That has its own set of side effects, such as creating a horrible experience for the most talented and active players — also the ones most likely to stream and advocate for your game, to produce youtube videos to complain about bad experience, and to have a very influential profile in the community.

The state of game cheating has professionalized A LOT, it is extremely competitive and cheating companies produce extremely good quality tools compared to what we had 20 years ago. There is a lot of money to be made, we are at the point where you can just pay a cheap monthly subscription and you get access to actively maintained cheating tools. I know people working on the anti-cheat side, it is a really messy, highly dynamic (the bad actors are constantly adapting), complicated problem that isn't solved once and for all. We are far from the situation where just a few people are using some hacked-together software that will obviously be spotted as cheaters.

Game dev companies (at least US/European ones) have zero interest in developing or paying for kernel-level anti-cheat. That's a massive barrier of entry for the player base and they know this. It's also far from being cheap.

(Note: ignoring geopolitical factors, Chinese companies such as Tencent or Russian companies could definitely have interests in developing kernel-level anti-cheat for information gathering)