Competition in this game does not need to involve in-the-same-instance PvP - the whole game is effectively designed around indirect asynchronous competition, where all players affect game features even if they don't or can't (due to P2P connection quality issues) instance with each other.
Which "other ways" are being suggested that don't require PvP that "solo and private play severely hamper"?
Which is what I was getting at before getting instantly shot down above because it's ~spooky~ PvP. But as it stands now, no, the entire game is not designed around asychronous competition for the simple fact that there is no route by which you can hinder or decrease the efficacy of those players progressing systems in their closed safety bubble. The only viable and possible route you can take is earning merits faster; which at this point only amounts to a race to trade more rare goods than your enemy. So in essence the entire feature is designed around gathering generic unit x, hopefully faster than your enemy, ad infinitum. Being able to slow down, hinder, add difficulty, ... to the amount of generic unit x your opposition makes is sorely lacking in order to even imagine this feature being "designed around indirect asychronous competition". Designed around monotonous hauling gameplay that we've had before the feature is more apt.
As for your request for examples;
I can, from the top of my head, think of NPC based hindrance. Allow for agency in a strategic increase or decrease of hostile NPC's in a given system to, at the very least, give a bit of kudos to the pretense that there is strategic warfare going on. Modifiers in some way shape or form could also be possible. This is more direct but; allow PvE activities to occur behind front lines as a logistics esque deal. Not entirely risk free but neither full PvP either.
Though none of them come close to what "same instance PvP" could solve, but we're so averse to that.
shrug Any more thinking on the subject and you'll have to hire me.
When catering to PvP players necessarily means effectively removing the ability for players in modes other than Open to affect a game feature, why should those PvP players be given something that is currently shared by all players at the cost of taking it away from players who have no interest in PvP?
Noting that all players bought the game on the same basis, i.e. three game modes to choose from and mode shared game features to experience and affect from any game mode.
That some players can't accept that other players don't need to play with them has been obvious for about a decade (in relation to this game specifically) - that's not a fault of either the game or those players who don't need to play with them.
Aye, dumb down a feature to obsoletion or make it interesting in order to cater to more people, not just scared risk averse players? Good question.