The US market, while still important, is no longer the only arbiter of success. The international market is actually more important for many movies. The number that blew me away was that "Harry Potter and the Order of the Phoenix" darned near broke ONE BILLION DOLLARS worldwide in ticket sales alone, with $938 million.
The Lion King was the first movie to break a billion, but that was with 780 million in ticket sales. The billion was broken after adding in VHS and DVD sales, soundtracks, toys and related merchandise.
Production budget is only part of the cost. Marketing costs are a bit**.