While poker is not easy to master at a competitive level, for those lucky few who are particularly talented at the game it is easy to make a comfortable living from the game. While it is a risky strategy as you will not always cover your losses, some tournaments pay out significant amounts of money that could easily subsidise a person or even a family.
Poker is not a stable income. If it is, you're either cheating or money laundering.
It also depends on the amount of readily available suckers.
Stick to a day job. It has far more security and less chance of IRS investigation, a run of bad luck, or sharing a cell with a large tattooed gentleman named Bruno/Bubba because they busted your money-laundering empennage.
Even if you are very good it is still completely up to luck and therefore can not be considered a reliable income. I especially think this is dangerous if you have a family to support or bills to pay. As a hobby it can be great fun, just not a sole source of income.
While playing poker can make people what can be considered an income, this should not be coined a viable source of income. Gambling of any sort is a fun activity to engage in and even more rewarding if you win. The risks taken far outweigh the monetary gain in most cases. This results in either frustration or a long term addiction. When looking for a reliable source of income, get away from those tables and get a job that has a solid foundation.
While there may be a minority(a very small one at that)who can make a profit gambling, many people have gone completely broke because of gambling. To suggest you could live on chance is simply that. Chance. Do some people do it? Yes. Most don't however. In this particular game of chance, there are more losers than winners.
The problem with playing poker as a viable income is that it is ultimately a game of chance, as games tend to be, and it doesn't even provide any of the same guarantees that, say, stock market investment does. Even in stock investment, one will find that they are contributing to a whole. Poker is simply gambling without reason.