[DubiousPusher]

> The Colossus computer, with thousands of vacuum tubes, was the first practical use for computation, in 1943.

I don't think this is true. Perhaps the Colossus is what we would call the "first computer" by some definition but electro mechanical computing devices built for specific purposes preceded it. There wasn't a 60 year gap of investment with no practical application of classical computing.

Classical computing was built up over time with practical utilith along the wya. The vacuum tube eventually became a useful component of it.