As a professional gambler, I can tell you straight up, that the probability of getting rich from any form of wagering is pretty slim.  Yes, there have been people whose stories you have heard of, getting lucky and winning lottery and/or Megabucks jackpots, or winning the World Series of Poker.  But if you take all the people who actively gamble in an effort to make money, you'll find out that few have the skills and discipline to consistently make money, and even fewer get rich.  One's specialty (table games, slots, video poker, live poker, sports betting, etc.) is irrelevant.

In general, about 90% of all gamblers will end up as net losers.  About 8-9% will be able to come out ahead, but not by any significant amounts.  Only the top 1-2% of gamblers are able to make a living at it, and just a fraction of those in the 1-2% end up wealthy because of it.  Amongst my closest friends are a couple who as professional gamblers, made over $100,000 per year during 14 years of a 15-year span (the one year they didn't, they lost about $50,000).  They live decently but are by no means rich.

Although I don't take up sports betting (my specialties are video poker and slot machines), my blog/ulog basically shows what happens on a day-to-day basis with professional gambling.  I'm considered a low-level player but am looking to move up in stakes as my bankroll grows, but even at the lowest levels, there can be some really ugly losses.