It took roughly a century from the discovery of quantum mechanics to when we started using aspects of it in real-world technology, even during a relatively primitive period of human history where we were also still figuring out mere electricity.

But I bet during the time quantum theory was first being developed it was hard to see how or whether it might be used in actual technology. I'm sure some even dismissed such possibilities. But here we are now using it to inform radio telecommunications tech, and experimenting with quantum entanglement communications and quantum computers.

A hundred of years of having the correct theoretical foundations + hacking and tinkering on them may make possible things that seem exotic or impossible now.

What? Quantum mechanics was used almost immediately to understand chemical bonds and to understand the nature of semiconductors. The frickin LASER is a quantum mechanical device! I could go on and on. The notion that QM wasn't used for roughly a century is totally false.

The laser was invented in 1960, 55yrs after Einstein published his Nobel-winning paper on the photoelectric effect. So great, in some cases it takes even less time to get from correct fundamental theory to useful technology.

The is point is - finding the correct theory sets off a process of hacking and tinkering that results in useful new technologies at some future time, some of which may not have been foreseeable at the time the theory was discovered. But we have to invest in finding the correct theory, anticipating eventually useful things will come of it, some we can foresee and some we can't.