There are people on all sides of Puppygate who are talking blissfully about the vast sums of money that must be flowing into the coffers of Sasquan, the 73rd World Science Fiction Convention. By the look of some of the comments, you'd think that the committee must be building Unca Scrooge's Money Bin on the banks of the Spokane River. Y'all need some perspective. I do not speak with inside information for this Worldcon on this subject. I speak as someone who chaired a Worldcon and had to sweat over a budget.
1. Despite what you may think, a Supporting membership is not 100% "profit" to the convention selling it. You may think, "Oh, it's money for nothing at all!" (which is the argument people use to say it should be $5 or free), but it does cost the convention resources to service the membership. This is what's known as variable cost: the amount the convention's costs go up every time they sell a membership. That includes paper publications and postage expenses for every member who requests them, and that's not trivial. In fact, for non-US-based members, it may well exceed the revenue realized on the membership. Another cost not considered is what the convention's payment-processing system charges per membership. There are others. So while in most cases, a Supporting membership does help support the Worldcon by helping to pay some of the huge fixed overhead cost, it's not like sending them $40 means $40 "profit."
(I suspect the concept that there are members not in the USA is likely going right over the heads of most Puppies. I despair of my fellow Americans sometimes.)
2. It currently takes about five Supporting members to equal the gross (not net) revenue of an Attending member. Thus the (as of April 12) 3,300 Supporting members of Sasquan are equivalent to only 660 Attending members. So the Supporting members (based on the April 12 numbers) may be 47% of the members, but they represent less than 20% of the revenue of the convention.
If we gave Supporting members voting rights in proportion to the amount of revenue they contribute to the convention, they'd only get one Hugo Award nomination per category, compared to five for Attending members.