Have you not heard of retro/revivals, and of art going in cycles?
Of course I have. But this, I don't know, feels a bit different to when I usually see retro revival stuff appear in the charts.
Usually retro stuff has a fresh spin and is almost a new sub-genre in its own right.
I think the 70s was quite a strange time culturally in the media anyway. It felt like a mish mash of all sorts of different time periods. On television as a kid we had Flash Gordon type serials from what must have been the 1930s, and cartoons and TV shows from the 1960s, Laurel and Hardy and Three Stooges type shorts which were from decades earlier.
I mean 'strange' in a good way by the way, as a kid it felt great having all this mish mash of different things from different eras going on.