Because while the point is to make money, the point is not to maximize the earnings for tours. Instead, it's to make enough to make it worthwhile, while giving

Because while the point is to make money, the point is not to maximize the earnings for tours. Instead, it's to make enough to make it worthwhile, while giving fans "what they want". Artists care about doing fun/good/cool stuff! This is similar to stuff like auctions to have dinners with certain successful people. Those people have many dinners where they don't ask for a bunch of money from the participant, because then they would only have boring dinners!