Dc has been infamous for the "This counts but that doesn't" mentality since immediately Post-Crisis. Supposedly, Marv Wolfman wanted a complete restart because he felt the whole Crisis was pointless otherwise. At the time, 1986, my friends and I would joke about things like, "Well, in this comic, Page one, panel one still happened but panel 2 now happened in a different way and panel 3 didn't happen at all."
Since then, it only got worse. I'll be honest. I rarely read comics anymore and, when I do, it's "Batman '66" and "Wonder Woman '77" and tie-ins and collections of old stuff. Part of that is nostalgia. Part of it is the price of comics today. But I still read certain characters. What made me totally lose interest is that it seemed pointless to get into a character when I'll read a great series and then, within six months to a year, the next writer just decides it never happened. That started way back. There was Shazam the New Beginning and then it was thrown out for Power of Shazam and that probably didn't happen long before the official restart. In my opinion, "Rebirth" was the best Superman origin story ever done and I don't think anybody treated it as canon and it might as well have not even been done.
I remember a Marvel editor when I was a kid responding to a letter where someone complained that around 1970 the characters should be going on ten years older than when Marvel started and joked about how Susan Richards had the longest pregnancy in human history. He just said, "Oh come on, we all know comic book time isn't the same as real time. Maybe in the world of comics, people just live a lot longer."
I almost wish we could suspend our disbelief just as we do to accept a man from Krypton who flies through the air so fast he's invisible yet doesn't cause tornadoes and use that same suspension of disbelief to ignore the passage of time and just say Superman started in 1938 and all the stories of all comic characters happened when they were originally published and just go from there. Of course, I realize there comes a point where new readers would feel the origins and formative years of the characters were no longer relevant.