I’d be interested in hearing why they can’t get decent anti-cheat on Linux. Are there technical barriers?

It’s extra hard on Linux because the amount of ways you can reconfigure a linux machine to work around boot- or root-kits, the ways you can modify a running process, and hide what is happening from an existing process.

Really, linux is meant to give you control over the software that runs in your computer. Anti-cheat is inherently about limiting what you can run on your computer. Windows is much more aimed at allowing you opt in to hard limitations.