The first question you have to ask when you’re figuring out whether the Boy Wonder could support his own movie is which Robin you use.
There’s Jason Todd, who was such an asshole that fans called a toll number to vote that he be beaten to death. Tim Drake, a pleasant enough kid who most people tend to forget exists. Stephanie Brown, Drake’s girlfriend who was Robin for like a week before being tortured to death. And Damian Wayne, the murderous son of Bruce and his lover/nemesis Talia al-Ghul, who was recently stabbed to death by his own aged clone.
Being Robin isn’t easy, and although two of the dead Robins have since been resurrected (Brown is now Batgirl, and Todd is now an even bigger asshole in the form of The Red Hood) there’s only been one Robin that could be said to have made a successful solo career.