I realize that, but I think after a 10-qubit chip is made, it will be easier to scale up.

This tech is aiming to be "mainstream". Google, IBM and others' quantum computers will likely prove useful earlier, but we won't see them be paired with our personal computers. This on the other hand, offers that opportunity, but it will lag behind other types of quantum computers in terms of performance.

I don't think we will get devices cooled by liquid helium at our homes in any short time.

But this makes it possible to distribute them at more datacenters that can be much easier to reach than what Google and IBM are creating.

This is not my field, but IIRC dilution refrigerators capable of sub-K temperatures are nowadays available off the shelf from a number of commercial suppliers. Which is a pretty cool (har har!) advance considering not many decades ago labs had to create their own, at great expense.

So in principle, there might not be any really fundamental issues preventing such things in every home, with mass production economies making them cheaper and more reliable.

The real question IMHO is whether this will be useful in some way compared to just connecting over the internet to some data center running them.

Safety is a fundamental issue. Home appliances don't get the best maintenance available, and supercool and high-pressure containers aren't easy to keep around.

What interesting things happen at 50 qubits?

We can prove that quantum computers are faster than classical computers at solving certain problems (like simulating atom interactions). Although IBM recently moved that goal post, and proved that we can simulate 56-qubit (and probably a little more than that) with classical supercomputers.

https://spectrum.ieee.org/tech-talk/computing/hardware/ibms-...

It's debatable how generic this 56-qubit simulation is. We can already "simulate" millions of qubits, with entanglement, as long as they dance in a particular way...

I figured as much. So whoever develops a 50-qubit quantum computer first (Google?) will have to prove that the same simulation can't be done with a supercomputer. And they'd need to be serious about it and use the latest research in classical simulation, including IBM's 56-qubit research to try and do it on a supercomputer.

Otherwise, they may claim "quantum supremacy" and 3 months later someone else will prove that the same simulation can be done on a classical computer.

You can't do anything interesting with ENIAC, but you had to build those before you built anything else :^)

The people that built the ENIAC did it to solve actual problems.

Well, every new technology needs a proof of concept first.