Supergirl and Arrowverse

No.130228922 ViewReplyOriginalReport
I love Superman and Lois and having to wait for a new episode for so long I decided to give Supergirl a shot. It's exactly what I was initially afraid S&L was going to be but I don't really have much going on right now so I just kinda stuck with it.
After the Crisis on Infinite Earths all the Earths from different shows are now one called Earth Prime right? So what's the point of doing that if they're just going to ignore that when world ending shit happens?
I haven't watched the Flash but I can't imagine there's any acknowledgment of Lex Luthor, Leviathan and the Obsidian VR lenses there. And I'm sure there's stuff like that in the Flash too.
The thing is apparently there still are other Earths. Stargirl seems to take place on a different Earth. And while not explicitly stated I would guess so does Superman and Lois. Although there still is a Superman on Earth Prime and he now has 2 kids just like in his own show. But now they don't even bother explaining why he's not helping Kara and her friends with Lex. Am I right on this or am I just missing something and I'd have to watch the other shows to get the full picture of what's actually going on?