Your friend does not make constant money betting because it always has a low probability of making money on betting companies is it is based on luck and does not happens all the time. It happens once in a very long time, so your friend is not earning money on a betting company because I might have lost a lot of money before he or she was able to earn this money that you said that he has earned.Yes, I have a friend who made millions on one accumulated bet. He stopped betting since then. Betting is more of luck in my opinion so you can't be sure of success.