Most people do not spend thousands of hours building something "not knowing what they're building."

On the contrary, in my experience it's much more important to "play" with a concept and see it working. Too many engineers think they're going to architect a perfect solution without ever getting code on the page.

A slapdash prototype is worth the weight of 100 tests and arch diagrams.

Note: I'm not saying the latter is not important. My comment is, it's ok (and encouraged) to do potentially throwaway work to understand the domain better.

> Most people do not spend thousands of hours building something "not knowing what they're building."

They sure do in my experience.

> On the contrary, in my experience it's much more important to "play" with a concept and see it working...

I agree with all that. That's the point: figure out what you're trying to do before building it. Of course you will not know everything up-front, and of course you would try things out to learn and progress, and, for anything that it's tiny, of course it makes sense to do this iteratively, working from the most pressing/important/risky points earlier.

Or, at least, it seems obvious to me.