"On a budget of $10 million, it made less than $800,000 worldwide. Producers pre-sold pieces of the film to investors, insisting that they'd make their money back on a known star like Uma."
Producers don't "insist" on anything. You make it sound like the foreign sales people pulled a fast one. And you're suggesting the movie lost $8.8 million. Wrong.
A movie like MOTHERHOOD can turn a profit. Or turn a profit for some. The world is carved into "territories". Some are individual countries, like Mexico, Russia, China, India, and then there's "the middle east" and blocks of countries. Distributors in those countries bid for the rights to the movie. Back then, DVD sales were strong so the bidding would be for theater rights, DVD rights (sales and rentals), video on demand, and cable TV. For smaller movies, cable tv used to be where the big money was--no theatrical release necessary.
So you make Motherhood for $10 million. Then distributors in Mexico say, Uma Thurman sells crazy amounts of DVD's here and they get the Mexican rights for 1.4 million. Then the Middle Eastern distributors pay $500,000. Then do you do that for the 20 or so major territories worldwide. If you stack up more than the 8.2 million, you win. And usually, you don't put the movie into production until you make enough pre-sales to know you are going to turn a profit--or come so close to the outlay that the risk is acceptable. Also, these worldwide buyers put up the money in advance. So you can turn a profit before the first day of filming.
These types of deals often impact box office with major studio movies too. To minimize risk, studios sometimes sell off some worldwide rights.
The $800k box office is irrelevant. If a distributor wants to put it in theaters in their country, pay for the advertising, and takes a loss, that's up to them. The ones who went straight to DVD and cable had no extra costs and probably turned nice profits.
So you've got the main financial entity that produces and sells the film and about 20 different distributors. Some might make money, some might lose money. But they know what they're doing when they pick up the rights to a movie. The Australian distributors of Motherhood didn't pay up like it was Kill Bill 3.