[mjg59]

For the most part, the bugs we've seen in recent history can be handled at the kernel level - there's largely no need for applications to care about them (browsers to an extent being a counterexample, but even then if you disable hyperthreading it can basically be ignored at the browser level). The floating point division bug was something that every single application would need to have handling code for. From a "What is the worst case outcome", the Spectre family of bugs may win. From a "What is going to require the most engineering effort to fix in software", fdiv would probably have been a much bigger deal.

[nextaccountic]

One option would be to have an x86 to x86 compiler that automatically fixed your code. In principle you don't need access to source and it could be shipped by the OS