There is probably some nostalgic influence, but it doesn't seem like that is the reason. There are many different truck companies that exist and try to tweak the design to improve some aspects. Some of these companies will be trendy for a while and have pro riders, etc. but most people stick with the Indy/Thunder/Venture trucks, which are almost the exact same design. I think the later part of the article is more accurate, it is a combination of turning, impact and grinding. It is not a coincidence that almost all street/vert skateboards have converged to the exact same shape & dimensions. It's some kind of unconscious 'survival of the fittest shape' thing going on now for many year.