It depends how much time they can afford for SFI activities. The ones who have not other activities or problems, have more time to find people whom to invite in SFI and who want to be and remain active. They have more time to explain and teach their team, also maybe some more skills to determine people to become active in SFI. It is absolutely obvious that also when one has some more funds, can stimulate and sustain better the team from this point of you.