I doubt if Harry Redknapp knows enough about speedway to bring in new major sponsors so your comments are just speculation. Glasgow is owned by very successful businessmen who I can't see risking their future by joining the premiership until it would be viable for them. Again, why would Recar or Plymouth want to take the same risk?
If this did happen, the Championship, as the most viable current league, would be so depleted it would be no better off than the current Premiership