It's mainly cultural bias, established early on when amateurs were publicising what they thought were the most notable contributions of different past cultures...

Which were built edifices, and the effects of war and movement of people.. Today we have the ability to travel over a wide area, digital cameras snap a place/idea easily. Just looking at Eternals last photos, when he took the "long" view from a mountain miles away, and put the barrows and stone circle into their perspective in the landscape.
Suddenly a small tribal settlement/clan springs into place... people are living on top of this high plateau conducting their small lives, ideas of religion and ritual devolved from the area around them, new ideas percolating slowly from the traders and travellers who pass that way.
Britishness is a stupid idea, you might as well put a pin anywhere in a history book.....