Given that my post addresses the modes, including the freedom to choose who you want to play with, and is in the modes section of Elite Dangerous forums, I think you might have missed something.
"In the absence of..."
I've been playing this game since the Alpha, mostly in Open, and it's hardly a "full time PvP experience." At worst it's a blue-moon PvP experience, and at best it's a once or twice a year unless you go deliberately seek it out experience.
There's major three reasons why I think Elite: Dangerous doesn't have the player base other MMOs do:
1) It wasn't primarily designed as an MMO, and it shows. Between the peer-to-peer networking solution, the rather odd placement of the chat, window, "guild" support only now getting added to the game, and a host of other issues, it's not surprising that its player base is smaller than traditional MMOs.
2) It has a steep learning curve. In nearly all MMOs, the controls are the same as a bog standard FPS. Elite: Dangerous is different. It doesn't play like a FPS or a traditional MMO. It plays like a flight simulator, which is a rather niche game genre. As one famous wit put it:
3) It's a space game. Space games have always been kind of niche.
While invoking
steam charts hardly proves anything, it's the only information we have about concurrent players of most games. When you compare Elite: Dangerous to the other space MMOs on Steam, Eve Online and Star Trek Online, its player base is generally more than the other two games combined, and frequently by a large margin at that. Keep in mind that the former is genuinely a "full time PvP experience," while the latter is a more traditional MMO, requiring
explicit consent to engage in PvP.
I'm personally of the opinion that Frontier went the route it did to minimize operating costs. This game has no on-call game-master support in the game itself, which is needed for the type of shenanigans that can happen in pure PvE environments. Add in the programming chores that a PvE mode would require, I simply don't see that happening. If Frontier had wanted a PvE mode, they would've done the work when the mode system was being created, not years after the fact.