No, it's not impossible and it's not too late. Things have changed though. But they've changed in good and bad ways. On the one hand, studios really aren't looking to give 'chances' anymore, about anything. They're all run by accountants and the name of the game is preexisting intellectual property and derivative works. Once in a blue moon a 'pitch' makes it through and we see something come basically out of nowhere but the individuals with enough power to allow that to happen are few and far between.

But, where the conventional studio system has become more cloistered and intractable, the independent moviemaking world has never been more vibrant and inviting than it is today. Simply put, the technology at our fingertips for making movies is extensive and capable and puts really powerful tools in the hands of anyone who wants to use them. We can even release and distribute on our own through Vimeo and Youtube and the likes. But of course that also means there's more saturation and a flood of uninteresting or pointless things being uploaded every day and the average viewer isn't really primed to go looking for the next Mad Max on Vimeo. But still, even despite all that, the best stuff often finds its way to an audience. If you think of any time you've ever linked someone to or been linked to a 'really amazing fan-made movie in the (whatever) universe!" or "Awesome short movie!" and you watched it and you enjoyed it, well just remember that 9 times out of 10 the people making these things were and in some cases still are, just random people with a dream to make movies, and in some cases their knowledge and ability might have been no greater than your own just a few years prior.

Of course there is still a big gap between that world and the studio world. I think in the 'for the love of movies' sense, it's never been easier to get started, but if you're thinking about success and being the next big thing, that's as hard and improbable as it's ever been.