Obviously, a dedicated location for a minyan costs money. Whether it’s in some open field, a room in a commercial building, a residence or a dedicated synagogue, someone’s bearing the expense (ie: someone owns the field, even if it’s the tax-funded township).
The more numerous or fancier the amenities, the higher the costs. Expenses exceeding donations and fund-raising events must be covered somehow.
Membership dues is the most common and fair-minded approach to bridging any shortfall, usually adjusted by ability to pay.
If nobody pays, nobody prays (at least, not there).
This isn’t rocket science.