The course you need is a pretty simple one. As many people do, you’re confusing Leavers with hunter-gatherers. All hunter-gatherers are Leavers, but not all Leavers are hunter-gatherers.
The Maya were Leavers but had a civilization that was the equal of contemporary Taker civilization. Their calendar was better than anything we had at the time. They had the same impetus for scientific advance as we did. However, in the end, they became disillusioned with civilized life and abandoned it to return to the hunting-gathering life.
Hunter-gatherers have no discernable impetus for scientific advance. No known scientific advance has ever been made by a hunting-gathering people. (I certainly wouldn’t call the discovery of fire to be a scientific advance). But this is not to say that scientific advances would not be made in a Leaver civilization.
Just to keep the record straight, what I’ve said is that humans have been technologists from the beginning, and no Leaver people has ever been found totally lacking in technology.