it is because of something to do with Superman Copyright Court Case years ago?
Another article news suggests spalt Superman in two. But doesn’t work that way, also DC use Iron Munro mainly served to replace Superman in world war 2., but Iron Munro is no Golden Age Superman.
I don’ t understand why DC wants to bring back pre-crisis mix with the post-crisis timeline. I don’t know how that works?
Also says Jon kent will become the next Superman in 5g in next year. 
I think that DC does not want to have to figure out how there could be two Supermen, unless one of them was not from Krypton, was not Clark Kent, etc., all the things that are usually different between versions (like the differences between Jay Garrick and Barry Allen).
yes, it weird has two Supermen and two Clark Kents and two Batmen and two Bruce Waynes.
Clark has Jon and Connor, Jon is next Superman.
I read comics long before crisis when there were multiple earths. Having 2 Clark’s 2 Bruces was never an issue for me. The costumes were a tad different and Kal-L having a bit of grey at the temples was a dead giveaway.
Frankly I think they dint want to use Kal-L as so many people would think he’s the kingdom come version.
Yes, but they weren’t existing on the same Earth, in the same timeline, which is kinda what we are talking about here. That said, they could create a better replacement (similar to what they tried to do with like Iron Monroe but much closer to the real thing, sorta like Hyperion) and have him fill the role of the original Superman (same with Batman, etc.). A whole discussion could be had about whether Wonder Woman is more or less interesting if she’s a contemporary of Superman/Batman or of the 40’s era heroes.
Or both.