I live/work in Waterloo and regularly ask a favour of the Quantum Nano Centre folks at UWaterloo for a tour. Every time I look at the "computer," housed in a gigantic facility where each qubit has its own liquid nitrogen cooling unit and who knows what else plugged into it, and think to myself - I'm staring at the vacuum tube of quantum computing.

Yes, you can scale up vacuum tube computers to solve meaningful tasks, but it was barely more cost effective than human "calculators" except for specific applications. I think the same analogy applies for modern day quantum computers and classical computers.