Cash cow is probably a bit strong but it seems that it should be revenue positive. What is the bottom line? Is it self-supporting? Is it a yearly fund raiser for other much needed but less revenue generating projects of the AHA? Just doing some quick math - at ~$200+ a pop to attend the conference for 3-4K people, $12 per each of the 7.5K+ entrants and the revenue generated from the retailers - it would seem to be approaching a cool mill in total revenues. Without knowing the finances I can only guess.
If it is indeed self-supporting, then don't raise the fees. If it is in the red, then do what it takes. Just don't borrow any money from China.......
From the GC report, the Conference has been profitable since 2007. Before that, you can infer some years were not.
There are many costs that have to be taken care of, Security, cleaning of carpets (beer you know), the BA and AHA staff that make it happen, the cellar crew, the refrigerated space, the hotel staff that sets the conf rooms up and turns it around for the banquet, the list has to be long.
If the Conf. and competition make some money, then that would fund other activities and more AHA staff to concentrate on the AHA members. The Research and Education Fund would be an example (see the GC report).
Remember that the AHA is a nonprofit.