In some ways cycling is a victim of its own success. It's become popular and more diverse thus peoples expectation or wants from a club reflect this. Also it's not about numbers either.
Clubs need to be honest about their offering OR prepare to become more diversified if they want to attract large memberships.
When we founded 'Abingdon Freewheeling' we were a bunch of similar amiable cyclist who wanted to get people into social group riding, there's no pretence about speed or sporting, just rides aimed at going for a spin and meeting other cyclist. The other important decision we made was to be as unstructured as possible, hence anyone can start and lead any kind of ride they like, anytime. If it's popular it grows and becomes regular. There are no hard or fast rules.
We did have an influx of more 'mamil' types that wanted to convert us to a more 'regular' road club with higher fees and matching kit etc. It was an unpleasant time as we tried to stay true to our original ethos. We stuck to our guns and suggested they start a club on their own image .... They did and it's working well. Some ride with both groups, we all do our own thing and I think the cyclist of Abingdon are fortunate to have many choices.
There's nothing stopping anyone forming their own club in their own style, if the offering is good, people will come.
In the future there will be clubs for all kinda of cyclist ... And it only needs to be a few people.