One can be paranoid in a completely different direction, like “any quantum computer can’t survive long enough to perform any useful computation because objective collapse theories are right, the whole post-quantum cryptography exists to push implementations with backdoors injected by government”.

I have this type of tinfoil hat. I put it on whenever I see people blindly merging security fixes in response to vulnerability scans.

We're likely to see hybrid PQ + ECDH key exchange for the foreseeable future, running the pair of exchanged values through a hash-based key derivation function.

Partially due to fears of backdoors, but also out of caution because the mathematics of PQ cryptography has seen much less attention than DH / ECDH / RSA cryptography.

For a long time, there was similar conservative skepticism regarding ECDH.

The paranoid answer is to assume that certain organizations (e.g., nation state intelligence services, corporations that have enormous capital available, extremely wealthy people who can create organizations to pursue this) already have quantum cryptanalysis capabilities or very soon will.

In any case, it does no harm to be ready for a PQ world.