It is almost impossible to overstate how wrong the "not unique to any people, culture or time" idea is, as if it were something that comes naturally enough to actually work.

It doesn't. Humans had thousands of years to understand life and the universe, and we pretty much were clueless until we got serious about science, and then it only took about 400 years.

It is exactly the intellectual and cultural differences that explain why science has been so successful. Indeed, you see it repeatedly throughout history: for a little while, people start getting the idea to rigorously and systematically test ideas with evidence and progress takes off. But prior to the 16th century all these local, limited takeoffs got squashed by sociological factors.

You also see it repeatedly throughout human endeavors themselves: those that test rigorously against reality make spectacular progress; those that won't or can't wander along with little measurable progress.

The demarcation problem is important in that it's nice to know whether we're approaching an area in a way that ought to enable massive progress, or if we're going to be doing our tribal primate thing jockeying for prominence and telling emotionally rewarding stories to each other.