99.9% of poker players don't have the means, ability or even the desire to let poker change their lives. But for everyone else, poker can certainly change your life! Can be a good change, can be a bad change.
The sheer volume of people playing says that there must be people out there that could be among the world's best poker players, but don't have the nerve, bravery or financial ability to take that risk.
On the other hand, there are certainly those who have taken that chance, given up everything to take their shot, even on a lesser scale...and shouldn't have. A negative life change.