Alrighty.
The reason that ED doesn't have player-built structures is because its instance based server architecture doesn't allow it. The reason ED has that server architecture is because its non-prescription pricing model doesn't generate enough income to fund a single instance server like EvE Online has.
EvE Online does since recently offer free to play accounts, but it took 14 years of healthy funding by subscription to get there.
Having said that, Frontier has to consider what kind of game it wants ED to be. The first games were very much open-ended: here's space, you go do your thing in it. Objectively speaking, ELITE did not allow you to do much, but it allowed you to do it at your own whim. No rigid narrative to follow, no set levels, no cumulative mission objectives leading to a defined conclusion or outcome. No quest, no climax.
Elite II was more of the same, but in a bigger universe with more activities to engage in. But basically it is the same: space trade/prospector/piracy/bounty hunter simulator. That's it; go do your thing.
Some people make the mistake of thinking that ED should be like, say, Mass Effect, with a storyline and a quest working towards a climactic conclusion, that the player is at the centre of. Frontier made the mistake of trying to meet those expectations with Power Play: an artificial Game of Thrones like narrative that patches badly on the game's activities where the player is very much not the centre of the universe --hence there is no direct way to get involved with this narrative, only very indirectly through the usual player-centred activities acting as some vague proxy. And because ED is fundamentally open ended, that narrative doesn't actually go anywhere, ever. There is no progression, no resolution and no climax --there can't be, because in an open ended game there can't be a Game Over-- so all activity invested by the player ultimately remains unrewarded and pointless.
Basically the problem is (to borrow psychological models) one of objectives vs value. Because there is no narrative arc: no quest with climax, player activities don't have any narrative imposed objectives to strive for, and no satisfying climax to give them a point. In order to be worthwhile doing the player has to be able to project his own personal purpose on those activities. As such, they have to have inherent value: they have to be fun to do in themselves.
What makes activities fun to do in themselves? That depends on the player's values. Some players like to explore, some like to create, some like to socialise, some like the challenge and skill of combat, and (unfortunately) a few just like to grief (because there are bullies with inferiority complexes everywhere--even in the White House). There is no ultimate point or objective to valued activities; we just do them because the activity in itself has meaning to us: it is fun, we enjoy doing them and we enjoy getting better at them.
Secondly, activities have to create a sense of accomplishment, so need a careful balance between challenge/effort and reward (RNG in Engineers breaks that relationship by making reward ultimately a random outcome independent from effort, which is why so many people don't like it).
Frontier needs to focus on the inherent value (fun) of activities rather than try to cast them as spurious proxies to to a narrative that doesn't put the player at its centre and ultimately can never reach a resolution or climax anyway, so what's the whole point? Power Play was a mistake --it's as disengaged as watching a soap opera through a neighbour's window across the road. Players should be able to create their own guilds and their own dynamic drama, that they are at the centre of and feels personally relevant to them. Players should be able to craft their own materials and products and services. Players should be able to create their own structures --but there may be server limitations to that. Frontier also needs to carefully balance activities in terms of challenge and reward.
Create some activities that are easy wins for the newbie; create very challenging ones for the experienced player. Don't homogenise the galaxy: have safe systems and very unsafe anarchies, have places that are searingly bright and hot; others that are pitch dark and cold. Space is hard: ED should offer hard for those who wish to seek it out.