jumpdeer Nice piece. I believe hardware checks (PAC, MTE, maybe CHERI) will contribute over time as well.
But hardware checks can help only if developers who receive reports of hardware-detected memory-use bugs act on them! Our colleague @fid02 has been struggling with, if I recall correctly, Proton and Microsoft about bugs caught by MTE. Unlike virus scanners, this is not an area with false positives: if MTE trips, there is a bug, and it's a kind of bug that has significant exploitation potential.
Developers arguably should be nervous because threat actors can just run apps on GrapheneOS to turn up possible vulnerabilities. And arguably developers should jump on these reports.