-snuggles- Frustrated Tidey is frustrated, nu? o:
I understand where you're coming from, though, dearie.
While I think we've all run into our lively-one-day-dead-the-next RPs, I do understand where you're coming from when you say that it really does take a lot of persistence for an RP to maintain its activity over a period of time.
While you can advertise for hours on end, trying to get as many members in a bulk load as you can, this hours-long venture may often leave what members you can scrape together yawning and wondering when they'll actually be able to RP.
This said, I think it is helpful when RP leaders try advertising for shorter periods of time, gathering a little handful of members, then going ahead and RPing (this way the new members can not only get a taste of your RP, but also get what they came for! [Roleplaying, hurr]). And, of course, doing this daily, or every few days.
It certainly can take a lot of effort on the RP leader's part, but doing this over time can result in an effective strategy for regaining members, and also fostering a group of active and familiar members that may even come online on a daily basis.