Depends on the odds when you are gambling against them. If you wager 100 bucks per game, 38 games for a season, that's 3800 dollars, if three of those are wins, that means 300 dollars to bet those, and if the return is 4-5 than it would be a big loss, even at 10x we are talking about 3k return, and you are still losing, you literally need an average of 13x return on 3 games to make that into a profit and that's very unlikely, I do not see odds 13.00 on opponents 99% of the time, they must be facing some championship level team at cup for that I suppose, not too many at premier league would have that, maybe relegation team and I doubt they would lose against them.

So all in all you need about 6-7 losses at least, that would make a lot more sense, and they may lose that much, they lost 5 for example, so if it is 8, that's a profit, still awful lot though, so you may still lose. If you did it this year, you may have lost money.