How much does exchange commission actually impact long-term betting returns?

People always praise exchanges for having better raw odds than sportsbooks, but how much does the platform's cut on net winnings affect your bottom line over a full season? Is it still noticeably better than fixed-odds bookies?

Exchange commissions apply only to net winnings per market, allowing disciplined long-term traders to retain a significantly higher overall payout compared to traditional built-in sportsbook margins.