I keep hearing "but we've proven that quantum computers can work with experiments"...
No we haven't.
“Experiment after experiment” has proven exactly one thing:
Quantum mechanics works perfectly in microscopic, heroically isolated systems of ~100 physical qubits for microseconds.
It has never once been observed to survive continuous measurement and error correction at a macroscopic scale (needed for Shor).
Once the entangled system gets large enough, it crosses the threshold where thermodynamics forces decoherence and classical behavior — no matter how cold the fridge.
What we've been doing so far is just increasing the isolation of the system from the environment to access more of natural scale of quantum behavior. But we can't isolate the system from itself.
So the limit is hard. Isolation gets us closer to it, but it can't get us past it.
QC is not coming for your Bitcoin, or for cryptography in general. Breathe easy.
