I think the more realistic reason we never had another Superman movie after Reeve's time as Kal-El was because they were too busy making money off the Superman IP on TV. Lois and Clark was on for four years, soon followed by Smallville that ran for 10 years. Superman Returns was a valiant attempt, but it couldn't fully commit to one "vision" as it were. It was trying to forge a new path, but also trying to be too Reeve-y and continue what came before. Brandon Routh really got short-changed in that role. The movie could've been great, if they had committed to one direction for it.
What's amazing to me is how staunch people seem to fight against a Superman that isn't Reeve. He was great and those original movies will always hold a great place in my childhood memories, but to be so closed minded as to not allow anyone else a shot at the blue tights is baffling to me. We seem to be ok with letting Batman get reinvented every few years, why can't Supes have that same leeway? West, Keaton, Bale, and yes, even Affleck have shown that Batman can bent in many directions without being broken(excluding the JL Whedon reshoots and one-liners). To be honest, Affleck is my favorite, too. He plays the old Wayne/Batman quite well, just not sure that that old age got transmitted as well in BvS as it did the source material of Miller's The Dark Knight Returns. Plus, if there's anything real comics fans know about their favorite superheroes, it's that there are multiple versions of them partaking in multiple stories by multiple authors going on at any one time. How is it they can't see a new movie Superman as just "a new author's telling, in a new universe" of the last son of Krypton?
I'll admit, I used to actually be in that camp. Reeve was the best Superman in my mind and while Dean and Brandon had ok takes at him, Christopher still held the top spot as quintessential(I never watched Smallville, but regarded it as a "prequel" type story that didn't play with the canon of the Reeve-verse). I went into Man of Steel with a huge wall up. It's taken a long time and a few watchings for me to realize how even I was shortchanging myself in not allowing a new version of Superman, and even a new version of General Zod. Let me tell you, Michael Shannon is fantastic in MoS. his Zod makes perfect sense and is actually more of an anti-hero, admirable in his desire to rebuild his home, as he was chosen/bred to do. Both Shannon and Stamp's Zod's were amazing, unique, and had very different origin stories. But one does not diminish the other. Such is the case with each new Batman, and for this thread's sake, each new Superman. Cain, Routh, Welling, and Cavill do not diminish how Reeve did, what Puzo wrote, or how Donner directed. They're just different tellings in different universes.
Hey, the bright side of all these comic book movies is that at least it's not a bunch of remakes of movies that don't need it like with the new Overboard. Hollywood is pretty much out of ideas, so I'm glad they're tapping into comics since there have been great stories in them for decades.