but also how they helped sell the game to the wider gaming public due to the sheer amount of press they got
That's certainly one difference between the big player events you highlight and some of the ones you haven't.
Another is probably that those three, and most of what happened with Colonia, had direct Frontier support to convert player activity into in-game consequences in a way that couldn't easily be automated.
People have been pretty self-promotional about some of their events without that official support/endorsement, but it's not had the same sort of breakthrough to the wider environment.
There's also of course a huge amount of luck involved. The Gnosis could well have misjumped with just some Canonn regulars and a few extras on board, and not have caught as much interest as it did. (The Gnosis later made a jump to another otherwise inaccessible nebula, was not attacked by Thargoids, and this is barely remembered...) Distant Worlds 1 could have been (as originally planned!) Erimus, Dr Kaii, and a few of their friends ... and therefore no DW2 at all. Jmanis might have had the week off and not UA-bombed Jaques Station. Someone might have stumbled across the Zurara three months after release. The Witch Head Enclave might have really taken off as a centre of player interest and events and that Interstellar Initiative might now be remembered as a big thing (and it deserves to, I feel - there was some really good content there).
The writers of elites story along with player actions within the game should go hand in hand, as that's when you get the sense you're a part of a living breathing universe.
And they have, in the recent storyline, where it makes sense to.
- the reason the Alliance are mainly fighting the Thargoids on their own, while the other two were barely funding AEGIS even before the Alexandria, is in part to do with how players managed the Witch Head enclave after its creation
- Volkov leads an independent Marlinist grouping not just because of the obvious impacts of collective player choices in the CGs, but also (and why it's specifically Volkov rather than one of the others) because of BGS activity carried out by players to preserve the Marlinist colonies against the PMF attacks which would ordinarily have overwhelmed them
- similarly, Hadrian Duval probably only managed to avoid being captured by the Federation because the character caught the imagination of a fairly large player group after his first overwhelming defeat by Patreus, and has ended up building a strong following (in a way that, say, Jupiter Rochester isn't)
- if Winters had won the surveillance CG versus Hudson ... well, I'm not saying the Federation would be in a good position right now, but the storyline certainly wouldn't have gone down the PDB route as much as it has, with Federal factions defecting.
- the attempt to sabotage Salvation's recent superweapon didn't succeed, but it was a sound idea by the small group of players doing it, and got a mention in Galnet as a result
- on a softer level, "Fednecks" seems to have been picked up as an official insult.
Obviously, ten thousand players taking some sort of semi-active interest in the plot, they can't all be integrated except at the most aggregated level. But still, some actions by individuals or tiny groups have got in, as well as some more organised groupings.
In terms of in-game integration (no comment on the story content either way, just the integration) I think the last year or so has actually been considerably
stronger than Premonition was. Part of which of course is greater in-game capabilities now than then - I'm sure Drew would have done more if it was possible then.
- the exploration bit of Premonition to find the Exodus settlements was pretty solid (though similar has happened recently with the hunt for the Hesperus or the Hyford's Cache event), definitely. Having the more casual multi-year search for the Zurara precede that also built a lot of interest, and that sort of thing is something Frontier haven't done as well lately. Codex rumours would nowadays be a great tool to start off a search, too...
- the Galnet content of Premonition was pretty cryptic and disconnected from in-game events at times (to the point where several of the articles, if you hadn't read Premonition but knew about the final event, you wouldn't I think conclude were part of the same story), with two of the early ones (the combat tournament, and the exploding asteroid) having been specifically called out elsewhere - along with the unrelated Gan Romero articles - as examples of Galnet content being detached from the game. Quite a lot of it in retrospect comes across as "and if you buy the book you'll find out why this was worth mentioning". Now, of course, most non-Premonition Galnet of the time was much the same...
- the climatic event was certainly very memorable ... though it is also worth noting that much of the positivity towards it and the storyline is only retrospective. A huge amount of the immediate reaction to it was negative, conspiratorial, denying of other players' rights to participate, and so on. I've thought a few times since about how you might run a similar in-game event which would allow mass participation not troubled by instancing limitations and not got anywhere - good event, worth a try, understandable that the conclusion was "the format doesn't work well in Elite Dangerous".
- there were also some earlier events between Drew's NPCs and player groups in-game, but from the perspective of someone not in those player groups then they might as well not have been in-game, as either way you only find out afterwards.