And that's a fine start, but my question was not why they avoided inventing everything from scratch themselves. Apprenticing to see how it can be done is only half the journey to understanding things from first principles, trying to then do it yourself is the other half. Usually you learn more in the second half than the first, you just need the first to make the second feasible.

Not that there is anything wrong with just wanting to make another visualizer and learn some things along the way, it's just a hollow way to try to learn first principles.

Were people not able to accomplish that transition in the times before AI existed?

This is the answer. Sometimes you don't even know the word to use to find information.