Big deal, a chunk of radioactive stuff and a geiger counter also generates true randomness based on quantum mechanics. https://youtu.be/QzI6GFzH7ZA

In cryptography the provability is the whole thing. It’s provably secure or it’s provably not secure. There is no gray area.

Nobody holds themselves to that standard.
As long as P=NP remains unsolved, they can't.
Even if we knew P!=NP, we don't know if integer factorization is in P, but many suspect it's not.

For those more interested in real world concerns, look into the NSAs elliptic curves published by nist. Many people used that without knowing how it came to be.