The game does get a bit dry after awhile. I know in V2, I flaked out early, started school and such, had no free time. Yeah, having two of them would kill off one prematurely. I was really thinking about doing a 1970s world, maybe like 1974-1980. That would allow for some pretty cool aircraft to be used.
As for active players, all worlds have that issue. That is why I like to try to keep worlds short, I am thinking 4, 5, or 6 years for the next one. Should cut down on the inactivity.
