One could imagine a sophisticated attack involving multiple patches to different subsystems at different times, that eventually converge into a Voltron-like monster once they’re all inside the kernel.
Potentially. However that also leaves a larger attack-surface, in the sense that more patches = even more scrutiny. Conceivably such a scheme would require all parts to be included (I mean, why make it larger than necessary?), so it would be extremely fragile to any single maintainer seeing the potential for abuse and correcting it.
> (I mean, why make it larger than necessary?), so it would be extremely fragile to any single maintainer
You answered your own question. :)
Your selected misquoting doesn’t help. A large attack surface increases the number of eyes.