but I see no reason to think they’ll just utterly fail at scaling production at those factories
Oh they’ll scale just fine.
It’s just that nobody will buy all those cars. They are already not selling them all, and we are about to enter the biggest recession of many of our lifetimes
Google is skilled at marketing. The only other new information is that they were able to prove that error correction capability scales faster than errors when adding ‘physical’ qubits. They use about hundred ’physical’qubits to emulate a single (error corrected) ‘logical’ qubit.
So once they are able to scale up from N=1 to something like 256, they will be able to do what you say.
Importantly, before that happens, let’s say for N=100, they will be able to simulate the behavior of chemical systems composed of 100 atoms. This is a huge thing, and your will hear about it long before they reach bigger numbers.
Scaling this number is not trivial. You should read about for example dilution regrigerators, and how to transmit a room temperature signal to ultra low temperature circuits. And then do that for tens of thousands of signal lines, (all currently done by hand).