I think if that was the case then it would be kind of of pointless.
I think the alternate reality needs to play into the main story somehow, otherwise it's just going to be some kind of random soap opera, with the characters just going about their lives. Almost like a different show altogether. There HAS to be some relationship to the island and the shows mythology, even in the alternate universe.
As you can see, I escaped the Island on a peddalo.