We know that current quantum computers are very weak. We do not know what is physically possible, or even feasible. Quantum computers today struggle with decoherence, but we really genuinely don't know for sure if they always will or if there is a way to overcome it. We have not hit a point where we believe we are up against hard physical limitations that can never be overcome.

> They are not able yet to emulate an i4004, let alone be a treat [sic] to "computing".

I am skeptical this is a good benchmark, though. How many logical qubits do you reckon it would take to emulate an i4004? I don't have the answer, but I wouldn't be surprised if you need less to do something interesting that a classical computer can't reasonably.