If activities were all funded by the participants, we would be very limited in what we could do. There would be little need for a chapter, it would serve as nothing more than a source of fancy titles.
Fancy titles will get you the ability to talk to people we would not otherwise be able to talk to.
Hence why I said "little need", not "no need". They can come in handy, but are a pretty minor part of what having a chapter is all about.