It is possible to make a living at online poker!
The question is what kind of living, you would need to have the Right playing skills as well as money management skills to do it.
At small stakes it is possible by playing 4 tables at once, someone that is a good SIT& go player can make $4 a tourney on average... 4 at once =$16. It only take about an hour for these so thats $16 an hour.... Thats not a bad living... but its not great either... The question about it lasting though is alittle debatable. I think the game will always be good at the low limits... So as long as you know what your doing you can get by. I say in 5-10 years It wont be possible to make a large amount at the higher levels, but lower levels will always be good.