More importantly we must not forget the ultimate paradox of the "Crisis"...because it happened, it can never have happened. (!) The final thing Crisis ret-conned away was itself, because no story involving multiple earths can possibly have taken place.
First, let me say that I've never read
Crisis on Infinite Earths. There, I've admitted my ignorance, so no one need point it out.
I have read about the Crisis on various websites. This free information has convinced me that I don't want to waste money on a story I wouldn't enjoy.
Nightwing has articulated a thought that has nagged at me. I've just never been clever enough or eloquent enough to put it into words. There is no post-Crisis explanation of the Crisis itself. Yet there are post-Crisis revisions of many pre-Crisis stories. Much like the historians in Orwell's
1984, the DC writers and editor can make history agree with the present.
I'm a fan of the pre-Crisis era. The Crisis doesn't appeal to me because it destroys those places (Earth-One and Earth-Two) and people (Barry Allen and Kara Zor-El) that I was familiar with and liked. The post-Crisis universe doesn't appeal to me because I don't see the point of having pre-Crisis stories re-explained to fit the post-Crisis "reality".
It seems rather silly to me that the Crisis itself is so popular among post-Crisis readers, considering that it is a story of an ending rather than a beginning. Its purpose is to end the pre-Crisis multiverse, something that it ultimately fails to do! After the Crisis, many series continued for months in a pointless limbo. For the Crisis to have succeeded, all series should have ended concurrent with the last issue of the Crisis. The next month, new series would begin to populate the new universe. No references to prior stories at all. Clean slate and new chalk. DC didn't have the guts to do it right.
Imagine that Superman, the Batman, Wonder Woman, etc. all appeared brand-new, without trying to back them into 50 years of revised pre-Crisis history. Forget all the old characters and start over. No JSA during the Second World War. No JLA during the 1960s and 1970s. Just new heroes starting out fresh. That would have been preferable to all the idiotic attempts to revise the past.
In other words, just because we aren't allowed to see it anymore doesn't mean the Multiverse doesn't still exist. We just got stuck on "Earth-Crap" for 20 years.
I'm with Nightwing. Gardner Fox was tuned-in to Earth-One and Earth-Two. The brains at DC today are tuned-in to Earth-Crap. I'll just read my old comics, thank you very much.