all RPs die.

What can we do remedy RPs dying prematurely?

The title makes me feel worse.
*exaggerated long sigh*

Make people actually commit instead of signing up in a whim, and then getting disinterested. I for example, never leave an RP without making at least fifteen posts. At least! Never!

I think all basically hangs on commitment. If people like not only their own character but also the others and the world and can dedicate some time, it should be fine

I think RPs should always strive to give off a friendly vibe towards everyone as not to deter those who may not feel like they have much to offer as an individual. Participants should always be reminded that any of the contributions they make, regardless of how big or small, does have a meaningful impact on the RP and that every player really does matter. No one should ever feel like they're inadequate because they think they're not as creative or refined in their writing or because they're incapable of stringing a bunch of BB codes for flashy CSS templates. I think that sort of attitude could promote apathy, because the participant automatically assumes they're not essential to the RP anyway. And OOCs should be more active and share open discussions relevant to the RP's events that could even allow non-players (i.e., fans who read the IC for fun or at least find the premise interesting) to participate without actually posting in the IC. Basically capitalize on the fact that RPing is a social activity and encourage anyone who's interested. Having memester discussions should never be exclusive to private skype chats.

Build a community. I think the reason Gunpowder has been so successful and for the most part continues to be so is because we talk about things and make plans together. Things go slow a lot of the time, but we're still invested in the RP because we get each other invested.

Which reminds me, the other thing that makes RPs die in my opinion is not when they go too slow but when they go too fast. If you rush everything your RP will fizzle out quickly. You want your RP to be more of a slow and steady burn than an explosion imo.

a) kickass setting that serves as fertile soil for player interaction that can last forever
b) steady and solid GMing - one has to be tireless
c) good company

a) and b) depend solely on one person, the GM, so the recipe for long-lasting RPs mostly depends on how good overall the GM is. But RPing is just a hobby. As there's no obligation to be thorough, and GMing is a lot of work, I believe some new GMs set out on their GM journey without taking it seriously and without having put the time to think it through (and rightly so, it's just a hobby like I said).

With c), if you're a new GM, you'll have to be lucky. Building a community like gimmepie said helps a lot. A bunch of like-minded people is a solid, reliable player base that can last for years, but it's a rare thing. Planets have to align!

It's really up to individuals to keep an RP alive. Theres so few of us, Macro strategies really won't do us much good. On the individual player, I think overall there needs to be more pro-activity and less pure solo-posting. The more involved a player is, and the more people they are involved with, the more I'd say there is a need to stick around, but that is something a player. There's definitely a fear of people leaving though, and that is pretty much unfixable, there are a few members that come and go like autumn leaves.

For GMs, the biggest thing they can do is stick around. A GM that disappears is an RP that dies (Dust was revived by the great Foxrally, so it isn't a complete death sentence, but I'd ray revivals are exceedingly rare). A GM that encourages their players, and the stories involved with their characters will also go a long way. I think some of us, and I am guilty of this, put more emphasis on our story over our peers, and that is wrong. A GM, even in a story RP, should really focus more on guiding than directing, that way players can get excited on what they can do next, while not worrying about how many surprises a GM will have.

Also, posting more is huge. Can't force people to post every day or every week, but two or three weeks between posts always makes me anxious.

If your going to be serious about running an RP, you should set up a discord chat or skype chat made for that RP to keep in contact with everyone. Pokemon Odyssey has always been running fantasticly since we have our own Skype chat to make sure everyone is doing alright (heck all of our posts are joint posts as well so character interaction is alot more fun)

That's just my two cents though. Pokemon Trainer Academy did the same thing for awhile also and that ran on for a pretty long time as well. Just keep in touch with everybody and keep your ideas interesting and heck, even share them with the skype/discord group if anything.