In the old days, tournaments were supposed to be run at cost. There was a threatened boycott of Fools in about 1990 because the TDs included their own substantial time as a cost of the tournament (if memory serves). Only gradually did it become even ponderable for TDs to "make money". Even now, though, I would be surprised if any TD got a decent wage (say, more than minimum wage) for his work.
The UPA Series really should be different because the players do not have the option of voting with their cleats and skipping the tournament for something else. The TD really is just the director of the event, not the owner, and so doesn't deserve the entrepreneurial rewards.
So, I'd break down the "profit" into two components:
1. A fair wage for the work going into running the tournament.
2. A fair return on the investment (and risk) of running a tournament.
I think we've reached a point where #1 is permitted (really, 15-20 years ago it was not) and ought to be the standard, although I'm not sure what a fair wage would be, especially since the TDs generally also need volunteers to line fields and man tents, and if the TDs get paid then the volunteers will want to be paid. And maybe we're breaking ground on #2 with the professional services of Cultimate. The NUA couldn't make a go of it.
Then again, in the real world prices are determined by supply and demand, not by the actual costs of producing the product. The actual costs relative to the price then can affect the supply, as producers either rush in to garner profits or else rush out because they can't make a profit. For other participatory sports, it seems that the going rate is about $5-10/hour for short events (1-4 hours) (a four hour round of golf goes for $40, indoor soccer is about $10/hr, my modified fast pitch softball league is about $3/hr, gyms sell one-day passes for $10). By this token, players should be willing to pay about $50 per person for a tournament, but somehow this seems excessive. One of the attractions of ultimate is that it is such a cheap sport to play (just need a pair of cleats, a piece of plastic, and the occasional ACL surgery).
The bottom line is that we've become spoiled (or perhaps we should say, "Ultimate doesn't make people spoiled; it reveals that people are spoiled") and might have to be willing to accept capitalism and all the good things that selfishness does for the world.