Players create the only interesting events in the game: Lugh, Mercs of Mikunn, Unidentified Artefact (Artifcat) research, typo-free Galnet stories, Code / EIC / etc subplots
What do solo players create: "If Frontier adds guilds I'll quit!"
Come on guys, can't we all just get along and add guilds?
The system-flipping events you listed were directly influenced by the actions of solo players. The UA research doesn't exclude solo players by it's nature, and there's no evidence to claim that that no contributions have been made by solo players.
The stuff whereby PvP crews waggle their weapons at each other and badmouth each other on reddit isn't that interesting to me, to be honest.
I'd prefer some lore from the Elite universe in the game, and for gameplay (and any in-game player groups) to revolve around that stuff.
Procedurally generated history/culture/genealogy/customs could have been done if Frontier had the will, and it would have added a lot of flavour to the game, making each place feel unique.
I don't blame any player for wanting to create their own stories. There's a serious lack of material in the game itself beyond the "Powerplay Of Thrones" soap opera, which feels somewhat bolted on. There's a whole galaxy out there, but right now it feels a bit like the players have to invent their own personalities to attach to each system, as if we were all Tom Hanks in the film Castaway, and every planet was a (slightly different looking) basketball that we had to name.
Persistent NPCs will add something, as long as they come with a bit of character and (ideally) a backstory. If they're just another PG name and combat rating, then they're not really going to feel any different from the random NPCs we already have. (Of course, having the history I mentioned earlier in the game to draw from would make giving each NPC that extra flavour would be a lot easier, as they could be tied in with it.)
Some of the stuff that No Man's Sky has, like freighter ships hanging around stations or outposts, with tiny shuttle craft flying between planets/freighter/stations/outposts, would make this game feel more alive and human IMO, even without having little people running about everywhere or faces on comms links.
Hidden outposts...secret human settlements beyond the frontier...there are hundreds of things that would be far more important to improving my experience of the game than player pew-pew clubs.
I don't even mind the idea of including some form of Power-specific communication. That's not the same thing as guilds, but not too far off, and it would feel more like part of the Elite universe than some meme-ridden guild that a few players decided would be a thing in the lore now, so let's pander to their desires and forget those authors that paid good money to Frontier, and put a lot of thought into their creations so as to fit in with the existing lore.
If we end up with Galnet articles detailing the latest political conflict between "On Fleek Crew" and "The Brony Bunch", it would be a shame. I know that some people would love that, but "they're all morons who I'd happily leave inside a burning building to save a pig" (copyright Frankie Boyle)