The hell are you on about? There really aren’t any trivially controlled resources in null at the moment. The closest is moon ores, and even those are pretty accessible to smaller groups.
Just about any group of jackasses can go get some sov if they want it.
Your “make it all contingent on one super rare resource” just means goons/panfam/deadco/legacy will go to where those resources are and control them, easily, in a way that cannot possibly be contested because now you’ve made it ■■■■■■■ impossible for anyone to even get the ships they need to contest it.