From how I have always seen it, the point is to have seperate planets with seperate economies that intersect via space... having nothing to hinder the movement (like lootable space) would make the entire game one big economy and then you may just as well have only one planet.
Doesn´t need to have lootable space to have seperated markets.
We had something like seperated market CND/Calypso pre VU10.
No storage at CND, transportation fee for auctions placed at CND to Calypso buyers.
Pilots had a good business transporting people between this two markets.
Traders could buy ores/enmatters at lower price than at Calypso, and could make a profit from transporting the goods to Calypso and selling there.
The costs of flights was higher than todays costs to fly to another planet.
This fact forced traders to buy bigger stacks at CND to get into profit after paying the pilots for transportation.
It worked, without lootable PVP.
Same would work with seperated planeteconomy!
We already have seperated storage.
We already have seperated auctions.
We would need, seperated auction history for each planet!
We would need drasticaly higher cost to fly planet to planet.
Higher cost to fly would force traders to fly with bigger stacks to get into profit or place at higher price at destination planet.
Not an option for every low cost noob miner/hunter, as the return out of a 50-100 PED run, can´t make them the profit needed to cover the flight costs.
As said, I am not against PvP nor against lootable PvP, but I would still prefer some safe routes that could be used at much higher costs to fly there.
Actually the lootable space does more bad for eachs planet economy than it is good to keep markets seperated.
Use of MS service may be an option, but hell no MS is save from beeing looted. A well organiced pirate gang, surely can take down every mothership in no time. That it didn´t happen yet, says not that it is not possible. It may happen sooner or later.