I asked about this on the webDiplomacy forums and they have confirmed that this is indeed the case.
Despite my willingness to play one-day turns, I feel two days actually gives everyone enough time to plot and counter-plot. The problem, as previously stated, is when defeated players simply check out of the game, leaving everyone else hostage to their sulking.
I think the biggest problem is that it’s all or nothing. Every phase is two days, even retreats and builds. Two days of negotiations is reasonable, but why anyone would need two days to figure out where to retreat, or where to build is beyond me. It would be nice if we could set those phases to one day.
It would be even better if people would hit the ready button!
Apparently automatically disbanding units where a player has lost all their SCs is technically unfeasible. However, it would be possible to add the option to have different expiry times for the retreat and build phase. They prefer to only have the one option to keep things simple, but they might add it if there’s sufficient demand. Here’s the thread: Phase length applies even to obvious disbanding? - webdiplomacy.net
Bumping this, case anyone wants to brag/vent.
Missed the last move last night because I had to go to bed. I was okay with Russia stabbing me to end the game, but I wanted him help him take Marseilles as well, just so I could count coup on France. Sigh.
The game still asked me (France) to disband/retreat, before formally crowning Russia the winner. I was the only one that had to do it, just to - you know - rub it in.
I’m happy Russia’s final move was to stab Turkey in the back, rather than taking Paris.
The original plan was to take the remaining SCs from France and Iberia, but the last couple turns were really dragging on. So I messaged Turkey and told him I was going to wrap it up.
As an aside, I’ve never won a game of Dip before and I’m not certain I’ve been in a game that didn’t end in a draw. Based on my readings it seems like a solo win in 1909 is pretty uncommon, usually they take until 1911-1912.
Incidentally, new thread with link to new game over here: https://boards.straightdope.com/sdmb/showthread.php?t=862538
New players welcome.
Good game, all. I feel like I acquitted myself reasonably well for never having played before. At least I wasn’t the first to go down. I learned from my mistakes.
Terminus Est, you’re a mensch. I enjoyed being your ally. Sorry I couldn’t throw the game to you at the end.
I really enjoyed playing with all of you, even the Omni and Horatius. Apparently the old adage “the only way to defeat Italy is to become Italy” isn’t actually the best course to take. 
When you didn’t take Brest in the opening round, I knew I could count on you and resolved never to betray you. (Until I had to.)
Just popping in here to catch anyone who wasn’t aware of the new game thread. We have a new game up, and we just need to get one more player to sign up in the next nine hours. Please take a look at Doplomacy II here: https://webdiplomacy.net/board.php?gameID=228870. You must share my addiction!