I kinda agree with the OP to a certain extent. One of the problems I see is that I could have found a good trade route, or a nice mining area and things can change without it being clear why. Players not in the open group become part of the background simulation and so it becomes impossible to team up with them or challenge them if I want to claim a resource or a route.
You can never "claim" a resource or route in this game. There is no persistence or static territory as in other games (EvE).
Find a nice mining spot, mine it out, then fly away and pop back into the instance generated. The asteroids you just mined will magically refresh with new minerals. If too many players are trying to mine the same area without solid enough P2P connections, or if it goes over the 32 player limit, the game will just create another instance of that resource area for the next group of players. It's not persistent.
Same thing with trade routes; you can't blockade stations because the game will happily create additional copies of that station if P2P connections aren't strong enough, or it goes over the 32 player limit. It's not persistent.
Between that aspect of the game design, and the dispersion and thinning out of players caused by the size of the Galaxy, it should be clear why it
doesn't matter that players can switch modes.