The WWE has never booked tag-team wrestling well. Bruce Prichard went on record saying Vince McMahon has never cared for tag-team wrestling. Putting tag-team wrestling on its own brand won't change that. Just because you have a growing demographic, it doesn't mean it will translate to massive viewership. I think the women should have their own show on the Network like 205 Live though. Also, "rabid fanbases" don't translate to television ratings, otherwise NXT would be on USA in some capacity too. NXT is never even the #1 watched show on the Network, which should tell you something.
Again, no major networks would be willing to put a show on a primetime slot without any of the major stars. For this idea to work, they'd have to put Rollins, Reigns, Ambrose, AJ Styles, Randy Orton or Braun Strowman in a tag-team. And even if they do that, why would those guys be excited about that idea?