I've now managed to watch most of this; its fantastic. What I thought was really interesting was a kind of continuity of an ethic or a style. The original concrete transitions were so tight and aggressive they were almost unrideable. It seems like they promoted a super direct, aggressive style of skating that still exists today even though the park has gone through 40+ years of changes (all starting with a mere a accident, the council workers who built the first version having no idea what a skatepark was). I suppose the same thing happens in climbing communities, where a particular style gets perpetuated over time..