I think that depends on the game, or whats being encouraged by it, which is where Elite really suffers for me by trying to cater for everyones desires, leaving to no-one fully satisfied (and before someone smugly posts "PvE players are happy" or what not, I remind you to remember the salt fueled and hatred fueled outpourings regarding UA Bombing, or when a PvP heavy player group got official FDEV coverage, which show that is not the case).
Naval Action for example, had PvE servers that have been absolutely dead in comparison to the PvP one to the point they've regularly considered winding them down.
The problem with spreading the servers for me, as I'm sure we've discussed has always been at that point: Which 'server' counts as canon for lore and story driven event purposes?
PvEers are almost fully satisfied. Ok, a pure Open PvE mode would be better of course, but PGs is close enough for most of us i would daresay. We don't need that social interaction, and when we do, we can get it.
Its the PvPers who are unsatisfied.
Separate servers, should, in theory, give everyone what they want, and if the demand for forcing open is as high as some people like to make out, then surely a separate PvP server would do very well, right?
Naval Action for example, had PvE servers that have been absolutely dead in comparison to the PvP one to the point they've regularly considered winding them down.
Different games of course attract different players. EvE from the start was clearly full on PvP and anyone buying into that hoping for a PvE experience deserves what they get. Ark has many PvP and PvE servers, both types very popular. I guess with Naval Action the PvE gameplay simply wasn't interesting enough to keep the PvEers around.
One that stands out for me is Sea of Thieves, which is popular with both PvEers and PvPers even though it is fully PvP enbabled, or at least was. The devs did add a limited PvE mode, and i got really excited, until i saw just how limited you are playing it. I presume they want to channel people from the PvE mode to the "Open only" mode as it were. I suspect they fear that if they added a full PvE mode that the PvP server would die. Maybe rightly so. I'm hoping, one day in the future, perhaps when player numbers fall, they will offer a full solo or PvE mode. Would love to play the game.
Which 'server' counts as canon for lore and story driven event purposes?

Sci-fi universe. Its not like parallel worlds aren't a common meme.