That'd be a good way of getting players to not want to play Origin or for the Kangaroos! Have you seen the Prime Ministers XIII? Its getting harder to get players in the green and gold as it is.
What it will do is reward clubs for representative development within the club and also free representative players to pursue careers elsewhere may be Perth if and when Perth is installed, because clubs may have more than allowed therefore can't buy more from outside the club.
I would rather see Perth and Adelaide in the national competition to complement the cities of... Townsville, Brisbane, Gold Coast, Newcastle, Canberra, Melbourne, Auckland, Sydney (I'd put all the existing Sydney clubs in a Sydney competition like it was in the old days and have a Sydney representative team).
There are only two states playing state v state on a regular basis, New South Wales and Queensland because of quality reasons, so ten teams in the national competition are enough for a population of 25 million for quality reasons.
It's the dream of kids to play representative sport and also win a national competition.
Perhaps the Prime Ministers 13 is not high on the strength schedule because it isn't the World Cup or Ashes and an opportunity for developing players to get match time.