@ OP, perhaps the simple common ground between RP’ers, which is a love for RP, is not enough to create a sustainable platform or group but merely leads to a place where activity may flare up once in a while and then die a silent death.
I’m not in any position to discuss RP’ing in particular, but it seems to me that in order to create any group cohesion and longevity in EvE, the RP factor will always be an extra element but not a replacing one. What I mean by that is that the cohesion needs to come from core gameplay, and in your case positioned in or embellished by a framework of roleplaying.
A classic EvE example of successful roleplay, which started more than a decade ago was the one with CVA at its core, doing the usual EvE pvp stuff but with the side dish of fighting on the side of the Amarr Imperium and Empress Jamyl. In a sense you can even extrapolate their version of the resulting NRDS Providence region as roleplay. The real binding between these players-members came from the usual drivers: pvp, friendship, trust, reliability, holding sov space, but not so much the RP factor. that was a finishing touch. To this day it’s the only one I know of that clearly associated itself, for a period at least, with parts of the EvE lore.
Another example is the group around James315 and its Code, which thrived on pvp via a particular approach to the game - whether you love it or hate it is immaterial - and had a very interesting and entertaining web site where stories were exchanged in character. The binding factor was a love for pvp, for the extortion (…) and a solid knowledge of game mechanics. The outward identity (the RP) added to the cohesion of the group but didn’t replace the core elements. And above all, they created their own lore (the Code).
Beyond that it becomes very hard to identify real RP groups, although some do have RP elements. The Eve-scouts, with their rescue services and NRDS rules of engagement, are RP’ers to some (vague) extent serving all eve denizens via weather reports, thera connection mapping and wormhole roadside assistance. But above all they seem to love scouting, flying ships under any conditions, mapping - typical core elements of the game.
tldr;
Any successful attempt to create a group with long term viability, and RP’ing can be a powerful attractant, will need a common ground for members of that group based on core gameplay elements. The most powerful ones in my opinion will involve sovereignty aspects, or at least the control of solar systems. Lore is not really necessary, you can create your own. Perhaps I see the RP aspect too much as an extra garment any pilot can wear, but that’s the way I see it.
In conclusion: sending prospective RP’ers to a website, channel or w/e will never be enough. Incorporating them in an actively playing group (corp/alliance) that adds RP elements to the group identity will make all the difference.