Do you mean that it would be impossible for a team of experts in C and rust to rewrite pg in 5 years? That is essentially what he is proposing. (Which probably isn't a great idea, but I think the work scope estimate is in the right ball park.)
The way he proposes it, and the reasoning behind it all scream "clueless".
Reminds me of first year CS students who after learning that assembly is lower level and can be faster than C, wanted OSes and applications to be written in assembly for speed.
