Well - unfortunately this isn’t true. While troops might be self-sufficient (some aren’t..) the level up troops run ONLY on donations from the community. I’m talking about the council level offices. That place where you bought your uniform or the Scout Master ordered the merit badges costs money to keep open. They have staff there that oversees record keeping of the Scout’s advancement, coordinate operations of the Summer camps owned by the councils, etc. Money for these operations comes primarily from donations.
Things must have changed because I bought my uniform at a department store, and my gear anywhere. We only participated in a couple state or national events, though. Pretty much went to meetings and camped wherever. I try to donate whenever I see them, though, because I remember raising money for new tents. Was still in the Army surplus jobs when I moved away.