That practice needs to be ended.That's the point. They make many times what they cost to make, but standard accounting practices make it a loss on paper so they don't have to pay taxes or royalties to anyone owed them.
The biggest way they do this is setting up subsidiaries in other countries and then having those companies charge the company (the one set up specifically for that movie/franchise) massive amounts of money to market and distribute the film. They are essentially paying themselves (as they own the marketing/distribution companies as well) so that on paper it looks like the film made a loss.
The actual cost of marketing and distribution is much lower than they charge themselves to do it, but the more they pay for those services, the more money they can move into other tax jurisdictions.