Not only RP-wise, but generally this is true.We don0t have nearly enough members, mods or admins to support other RPs at the same level as the one we have now. It's out of the question to let this one die out, or stop improving it. Most RPs, successfull ones at least, require undivided atention and effort, and suddenly creating a site that houses multiple RPs will undoubtly mean you either get lots of Weak roleplays with moderate number of members or lot's of moderate roleplays with few people each.
So far we have one big RP with a lot of people, and even it isn't running as smoothly as it could be. The Admin can't just start hiring a ton of new Admin and mods, there isn't even enough members for that.
The RP has its shortcomings, due to several reasons. One being a large player base, others being inadequate amount of staff (due to the high amount) and so forth. If you're going to expand through multiple RP's (while a valiant effort) you're going to have staff that is inadequate and RP's that will be sub-optimal at best.