They must have. Otherwise why would they cobble it unless it was unfirm land. Also shows a pretty sophisticated culture with a division of power and an economy. They obviously managed to harness mass labor and to afford to diversify tasks in such a way that those people didn’t need to spend their day on tasks to feed, shelter and cloth themselves.
I think the concept that they were not as ‘intelligent’ as ‘we’ are, is a mistake of modern culture.
There could be other reasons for men in prehistoric times constructing a cobblestone path. Basically the same reasons ‘modern’ men do.
I think men can do, and have always done, anything they chose. What they chose to do depends on the environment they have to live in.
They built this prehistoric path, because they needed it, or because it looked nice in their yard.