I've had a bunch of friends that went from never gambling to spending a few hundred dollars per Sunday placing random bets. All destined to lose eventually due to the insane 10-15% vig (ie. a coin flip is priced at -110 or -115).
The few friends (sharps) that I had that were able to earn a profit over a large enough sample were all eventually backed off by the major sports betting sites. One site backed off a large long term winner in order to "protect the player against creating a compulsive habit or addiction". It's literally a racket. You can't win long term. You can only lose.