It's a bit hard to parse that sentence, could you rephrase?

Are you saying that untrusted code should only be run on systems which do not use hardware virtualization, because there's a risk of hardware bugs that require hardware replacement? The problem is that there is no single-system equivalent, users would have to use multiple laptops/desktops and air gaps to achieve separation (e.g. between network drivers and userspace apps). May not be practical.

Yes there's a risk of a catastrophic hardware bug with no workaround, but that risk applies to every feature in the CPU, not only virtualization or page tables or speculative execution. Statistically it's only happened once with the single Intel CPU recall, which are better odds than other risks.