Oh man OGRE MAGE, don’t even get me started… I know I am a recent arrival at the US Forums, but I would have a few choice words to say about your woes.
I am in Europe though, and it is getting pretty late on my end, so I will leave the bulk of my comments for tomorrow. But I’ll say I perfectly understand you. It saddens me to sense your demotivation, when your game is one of my absolute favorites in these boards.
More on this tomorrow.
EDIT: From my experience (not only in these forums, where I am a new arrival), I feel like PbPs are subject to a set of 'issues' which contribute to the fatigue you are feeling. In a nutshell, and for the sake of brevity:
- Sometimes expectations are not clearly laid out regarding the game, so you will get people who are more serious about their gaming vs others who really do not take it so serious and just come in for a quick post and get back to their real life. You will get people with a lot of time on their hands vs. others with less time on their hands. You will get people who like quirky, bubbly games vs. people who like dark, grim games. You will get people who like really challenging games vs. people who just want to be the heroes and defeat bad guys. You will get people who carefully read through the posts vs. others who simply skim, and because of that cannot really make very relevant posts themselves, so they mostly 'follow along'. Etc, etc. I know most of us (me included) as DMs do not want to 'keep people out' when we are running games, or heck we do not even know where the game will take us, so we might fall on the 'the game is more or less like this' approach, which leaves the door open for anyone who wants to participate. And I think that is a good thing. But I also think it can cause a real dissonance between the different expectations and play modes/habits different people bring in. While these different playstyles are most of the times compatible, in my opinion sometimes they are not. And it can be even worse when player and DM playstyles and expectations are not compatible - games become slogs, in which most are just unhappy to be there;
- Which brings me to my second point: one thing I have also noticed in PbP is people do not (usually) state openly to each other - 'Hey DM, thank you for running the game, but I don't think it fits my playstyle so on and so forth...'. They will instead just dwindle their presence away into nothingness, instead of simply leaving. As they dwindle away into nothingness, they delay the game by posting sparsely, make irrelevant or inconsistent posts, not paying attention to the narrative/story/gameplay, not paying attention to what other players are posting, and in general not engaging with the game, which is a normal thing because they are not enjoying it (or their lives simply do not allow them to keep up with the pace or content), but is also a bad thing because it can lead to the demotivation of others who ARE enjoying it. Faced with this, DMs do not usually ask someone to leave their games - I have been playing PbP games since 2012, and only very recently did I directly ask a player to leave, because I felt they were not a good fit for the game and my DMing - it is a HARD thing to do, and in the end did not 'save' my game, but I still feel I did the right thing. DM and players should be more open and upfront with each other on this, not to be an hardcore RPGer, but to make sure the enjoyment is shared by all;
I think there are a ton of possible reasons behind this misalignment between players, or players and DM, or DM and players - maybe people tend to overcommit to too many games, and then they do not have enough time to 'meaningfully' participate in each one of them, maybe people overcommit to too many games because many of them tend to fizzle out eventually, so they grab anything that looks interesting to them, maybe many games fizzle out because players are engaged in too many games and do not have time to post 'decently' in the games they are
We can go on and on down the rabbit hole, and never find an answer. All I know is I have been where you are OGRE MAGE, and I am sure most (if not all) people DMing PbP games have been there at one point or another. I have wrote a ton about the reasons why I think this happens, but I think it all boils down to the matching of DMs with players -
making sure the game the DM wants to run (in terms of content, pace, focus, engagement, commitment, you decide what is relevant for you)
is the game the players want to play, and vice versa. Be honest (and maybe blunt?) about it - in the long run it will be best for all involved, because much of this is also accumulated frustration that was never vented (speaking from personal experience), leading to burn out.
I would have much more to say about this, but this post is already absurdly long. Feel free to PM me if you want to hash any of this stuff out.
Last but not least, plugging my self interest here also

I really hope you find the energy to get back into DMing this one - I think you are doing a fantastic job as the DM. The game is challenging, with a ton of moving parts and urges the players to engage with it, pay attention or suffer the consequences. It all matches my sensibilities and my expectations, so I love it, and hope to get a chance to continue!