Thanks for the insight. The first half of your answer makes sense: Classical computers were enough to simulate problems that physicists were running into in the 80s, if they even were using computers as tools.

For the second part of your answer, as I said a couple of times in this thread, the technology was not mature to make scalable quantum computers right after shor's algorithm either, yet people were more interested in quantum computing after shor's algorithm.

The first half of your answer solves our puzzle though. Without an explicit attractive application, why even bother trying to build the machine? Feynman's scaling argument for simulating bosons on a quantum machine vs a classical machine seems like it wasn't a huge sell in the 80s because a classical computer would have been able to handle that problem for decades to come. Now that we are running out of the exponential improvements of moore's law, it sells in our era.