It's kind of interesting to speculate on how the megalith builders were truly revolutionary in many ways apart from the obvious. They took the old order of natural places being sacred and messed about with it to such a degree that by the time they had finished the 'landscape' was left barely recognisable. Deforestation, climate change, depletion of natural resources, new technologies, international communications, the trading of goods and ideas.... the list goes on. I guess there are parallels with today.
What's also interesting is what followed. The culture of the late Bronze Age/ Iron Age turned it's back on the stone monuments and returned to the veneration of natural places possibly led by a priestly class of 'neo-shamanic' druids.
All just wild speculation of course.