No
Not enough money, and still wouldn’t be a guarantee for Mafia, in your hypothetical.
Tim Donaghy only had 88% success rate in the NBA for covering point spreads (likely why he was caught).
All they really need is to have favorable odds like a 60% success rate of predicting if its a 1 goal game or 2+ goal game, with a ref in their pocket.
Do you honestly think that is not feasible?
You know that Casino odds for the house in blackjack is 57.88% they win right?
That's all they need. Odds to be put in their favour.
On a long enough timeline with enough bets, they win.
Infact, with the classic "Card Counter" only gains a 2.5% higher chance of winning than the house.
So with just basic math, do you honestly think its impossible that "make-up calls", "phantom calls" and "letting them play" are basically tools to tamper with betting odds.