Whilst mutual aid networks can take the diversity that more people joining the network gives them and use it to offer more services to other people in that community.
at least in the US, and from the experience of watching that happen, the problem is there’s more people that focus on the “aid” part and forget the “mutual” part. This causes the people who were reciprocating to leave because the returns were largely unequal, leading to an over-all deterioration of the services that could be provided by the group- which in turn leads to fewer people joining in the first place.