A lot of it can be blamed on inexperienced / unskilled GMs. Its relatively easy to come up with a good RP concept. Its quite another to make it work long-term. Sometimes, a good RP needs to be run twice to pan out right.

In addition, RL often gets in the way for players. If the RP doesn't have mechanics in place for efficiently replacing characters belonging to those who drop for RL (or other) reasons, it will eventually die.

We're into the 5th month of iteration II of Coruscant Sacked: Aftermath, but the original dates back to before the guildfall. It took a long while to fix the errors between the iterations, but in the end it was worth it.