According to Variety, a GTA film deal came close to finalisation last spring with "one of the six major studios" then "at the last minute, it all fell apart".
"I'm told Take 2 couldn't finalize terms with the studio, though I'm not sure if it was a purely financial issue or if, in the end, the publisher got cold feet about giving away rights to its baby," said the author of this.
A GTA film has been widely rumoured for years. That report reckons Eminem was slated as the ditched movie's lead, so it's missed opportunities all round, really. Maybe one day.