For hardware, you start with simplified CPU like a Forth or ZPU processor. One you can check by hand and eye on an older process node. Reverify it with itself. Then run above step for software on it. Optionally better EDA tools, too.
The diversity method ports the simple interpreter or compiler to a number of CPU architectures or dev tools. Pick whichever you want. If you aim for same binary, you'll need compiler designed to do that or reproducible builds like Wheeler links to up thread.
It's a question of priorities rather than feasibility. Most users or customers dont care enough to invest time or effort needed. End of story. Same one as usual for strong INFOSEC.
I'll also add that there already exists certifying compilers for C and Standard ML that both extract to ML. The ML extracted is simple enough to hand-compile to ASM following one of two guides. So, not only can oma human verify no subversion, there's already a production one with machine-checked proof that's also be checked by humans [again].
Yet, the world still turns, absent some terrible exceptions. It's almost as if no system is truly safe and secure, which I think cultures have known since the ages.