Only 'common domain' stuff like tailed beasts can have rules that can be universally enforced without imposing on the perceived rights of RPers. And since there is no set of executives but merely community consensus even with enforcing the tailed beast rules, it is difficult to find volunteers who actually want to participate in such a strict system. To my knowledge, significant amounts of RP goes on in clan halls and the like, so there are more than 30 people (I believe, don't quote me on this one) who actively RP.
You, to an extent, stated my point. Outside of tailed beasts, everyone has their own perception of what is good RP and what is bad RP, and have a tendency to reject what they consider "bad RP". When said groups are brought together and forced to RP, the notions that they have beforehand get in the way of cooperation, making something like cross-RP-type interactions difficult to facilitate. The biju, as "common domain", is a such medium where owners would have to either give up strictly adhering to their notion of good RP or not be a host. RP is all about give and take, and when there are IC fights where permanent death is a possibility, people are going to take far more than they are going to give in most of the cases I've seen.
It wasn't as much of an issue when you could die and come back next week as if you had not just been killed at all, hence why I had pushed earlier in this topic for all biju fights, if they were to remain, to be OOC, so that the consequence of death is not hanging over anyone's shoulder, and people might just ease out of the Alamo just a bit.