Option #2.

Edit: I ran an X-Men RPG for 10 years. It died a slow death, because it was focused on a core group that slowly dwindled until there were fewer and fewer of us. Instead of making 10 posts a day, we were satisfied that 1 post in 10 months was victory, but it wasn't the RP that we'd joined back in 2005.

A core group is important, yes. But without new players the people in the core group just dwindle away over time. And, yes, most of the new players will leave. If you get 3 and keep 1, that's what you want. Because that 1 can step in to fill the void created by the number of people we started with who didn't finish with us.