GPS sport is a construct. It was created on an idea and can be modified by a better one.
I love the NZ model of schools rugby where the best schools in the area (define that however you will) play in a divisional rugby competition. Traditional fixtures are still played within and outside that competition - but the best schools or teams within schools play off for what is effectively a state/ provincial/ area premiership.
Could look like for example (and this is by no means a ranking - just a means of demonstrating the idea):
QLD Div 1: Nudgee 1XV, TGS 1XV, TSS 1XV, BSHS 1XV, BBC 1XV, Churchie 1XV, Nudgee 2nd XV, Sunshine Coast Grammar 1XV
QLD Div 2: Brisbane Grammar 1XV, GT 1XV, IGS 1XV, TSS 2XV, Downlands 1XV, BBC 2XV, Lauries 1XV, TGS 2XV
QLD Div 3: so on and so forth...
Traditional GPS fixtures could be played in preseason if need be, and the old GPS premiership awarded to the highest ranked team at seasons end - irrespective of whether each school has played each other or not.
Appreciate there is a large number of complexities to this and my idea may not necessarily be a 'better one', but in my honest opinion protecting the GPS, AIC, TAS concepts should not be the barrier to preventing competitive rugby from happening, nor restricting schools from playing against higher level competition. Tradition is good, compromise is better.