Independent films step in to fill the gaps left by big Hollywood pictures. These days, if a movie doesn't have a superhero in it, it's probably an indie film. Unless it's a female superhero. Or gay superhero. Or brown superhero…if a movie has more than two non-white or non-hetero people in it, it's probably an indie film.
River Road Entertainment specializes in independent films, many of which feature rivers and roads, like Into the Wild (2007) or Twelve Years a Slave (2013). After Annie Proulx's story was published in 1997, the option for a film was kicked around Hollywood for a few years.
The most challenging thing about making the movie was just getting the dang thing cast. Few actors in late 90's Hollywood wanted to be a part of a so-called "gay cowboy" movie. Matt Damon turned down a role, along with Joaquin Phoenix and Mark Wahlberg, because they were "creeped out" by the gay sex scenes.
Screenwriter Diana Ossana campaigned for Heath Ledger and Michelle Williams, and eventually Gyllenhaal and Hathaway were added to the cast as well. (Source)
River Road co-funded Brokeback with distributer Focus Features. When Brokeback was released in 2005, the producers encountered some pushback from conservative groups, including a theater in Salt Lake City that refused to show the film because of its frank depiction of homosexuality. (Source)
But the joke's on the homophobes who didn't want to see this picture made and shown: the flick made $178 million bucks, nabbed three little gold men at the 2006 Oscars, and sent its stars into the stratosphere of cinematic fame.