You're conceding my exact point back to me. Linux-compatible anticheat uses many of the same pre-TPM measures that Windows 10 used to combat software cheating, and prevents the 95% majority of software hacks and process injection. The remaining minority of cheaters cannot be stopped on Linux any easier than you can stop them on Windows. Both OSes have escape hatches that cannot be easily closed.

Which is why I said, even if Linux enforced TPMs, secure runtimes and signed kernels, you'd still be loading firmware blobs and trusting HID/PCI hardware just the same as Windows. Linux would still be attacked, singled-out and made a pariah regardless, so it's good that Valve and the kernel devs generally ignore these design suggestions.

Prediction duly recorded. I sure hope you’re right, but I’m too cynical after decades of ‘ignoring attestation makes the underlying problem go away’ from my Linux peers to consider a positive outcome likely.