Gambling is all on luck; no matter how experienced a player is, if they do not have luck in their game, they cannot win. Because, even when some individuals go and have a better chance of winning for teams they know are really powerful by betting large sums of money, it is still all about luck. In football, it is not always about powerful teams; some weak teams might surprise a good team by defeating them, and that’s up to today. I do not believe that gambling is solely based on knowledge or experience with sports.
This is why there is ever no guarantee in gambling because no matter how long you are in here, or you say you are an expert, you won't win without the factor of luck.
Even with poker or sportsbetting where skills is needed. Still, luck factor is in play because if only skills, I would say, a lot of poker players or sportsbettors are already rich and at the top of their games.