I'm not sure if I completely agree, although I can see why people today would make the association between Chris Reeve Superman and the 1960s or 1970s Superman.
As I've probably posted too many times on this board, the first day I went to see SUPERMAN (1978) at the movie theatre, I sat through it twice. The first time, while I enjoyed the movie a lot, I was too stuck on all the ways it was NOT my Superman. So I had to sit through it again, to relax and enjoy it for what it was rather than what I had expected it to be.
How it's NOT the Superman of the 1960s or 1970s:
- Krypton is completely different--and Jor-El and Lara Lor-Van look nothing like themselves
- Clark was never Superboy and he never met Luthor when he was young
- The Kents live on a farm somewhere in the Mid-West (actually Alberta) and not near Metropolis (nor do they run a general store and Martha survives Jonathan)
- Jimmy Olsen is a photographer and he doesn't have red hair
- Luthor acts nothing like himself
- The Phantom Zone is absurd--some sort of flying mirror in space?
Furthermore, Clark is still a print reporter, whereas he was a T.V. news broadcaster in the comics at that time. And there are other inconsistencies that bothered me in the first showing. But by the time the movie came up on the screen again, I completely made my peace with that and accepted this as a different adaptation of the material.
To me, there was a lot in the movie that was referencing the pre-1960s Superman--the Superman of Bud Collyer, Kirk Alyn and George Reeves. Given a couple of the writers had done IT'S A BIRD . . . IT'S A PLANE . . . IT'S SUPERMAN--and that comes across as already out of date with the 1960s comic books--that might be why the movie has those qualities. At the same time, the movie was breaking with tradition and presenting the Man of Steel in a completely modern way, beyond what the comics had done with him (which is probably why John Byrne liked this version so much).
On the other hand, Christopher Reeve looked a lot like the Curt Swan Superman--which was highlighted by the publisher before the movie came out. And the movie's spirit felt familiar. So it wasn't completely divorced from what I knew Superman to be.