That wasn't the point. On a long enough timeline, the security of all systems drops to zero. If the entire world is running x86, then the threat model for attackers revolves around abusing x86. If things are homogeneous, it raises the bar and resourcing required to make attacks.

As always with security, everything is a tradeoff.

Your argument is basically security by obscurity. You're better off in an ecosystem where a lot of attention is paid to exploits and patches then in another where it might be a long time before a zero day becomes known and fixes are issued.

None of what i said is security by obscurity (which is also can be an effective tactic,but obviously not the only tactic).

There are only so many human hours and minds interested or allocated to exploitation and offensive security. If everyone used the same architecture for everything, the economies of scale on the offensive side (due to state funded actors) would blow everyone else out of the water.

From a software perspective, Windows has an incredible amount of skilled eyes on each patch release, but we still see new exploits. Same for Linux. Likely same for MacOS.

All i'm advocating for is that having separate hardware architectures is good because it raises the barrier to entry, even if it's only the next marginal step.

Security by obscurity isn’t even bad. It’s only bad if it’s your sole defence.

I am confident that my non-default SSH ports, that only accept connections after a sequence of port knocking, adds a slight bit of security to nothing. For example: xz backdoor.