In truth, it is quite likely that the Space X program could gain ultimate success. However, from my point of view, this would not be a one-time thing. Rather it would follow a series of steps. At first, this program must show prospects of being possible to the very least.
This would involve landing a small crew on Mars and getting them back alive with no health complications. This is something that I suspect could not be achieved within the next 10 years. Though it could be possible, it would take at least 100 years to build a small colony on Mars.