Which Sandro mentioned once and then never again. Restricting/removing access to content isn't a workable or popular suggestion.
IIRC Xbox players have to pay a yearly subscription to access open at all, FDEV won't (and shouldn't) remove content from the players who don't pay that premium to another company.
Have a read of it- in essence what it is saying is to beef up solo PP activities and make them a core experience of Powerplay, but drive that via missions instead of the tasks we have now. My idea was to have solo and PG PP players through doing Powerplay themed missions add to a CG like mechanism that unlocks better allocations / allocation times for Open PP players. With uncapped UM and being under heavy attack, solo players would have a vital role to play and in this way would be doing it in a fun, profitable way. At the same time, the hauling and fighting as we have now would be done in open. So rather than having an antagonistic relationship between modes they actually interlock and help each other instead. The great thing is that this is within the scope of that proposal, so in FD terms its realistic to achieve.
So no-one is cut off from content or needs a sub, everyone still has the bonuses etc. Its just rather than trying to fit a weak feature over 3 modes and failing, you use what works best and augment them.