[@silentmusician] Players are more active in 1x1 RP, and less likely to abandon a thread without warning, because then they know they're 100% responsible for the death of a thread if they do decide to quit. There's a shame factor, and a certain publicity to 1x1 which incentivizes people to stick it out long-term.

There are also fewer moving parts. If you're compatible with your partner then you're compatible with 100% of the other players in the RP.

There are other reasons but those are the two primaries.