Although the probability that a random referral will suddenly turn out to be a major high roller and can easily reach the 15th rank on the Betfury site is extremely small, it's still there.
James Wynn is a great example of how a referral can be profitable for the person who invited him. By the way, while Wynn was gambling hard on Hyperliquid futures and lost more than $100 million, his referrer made a lot of money on that. If I'm not mistaken, he received more than $3 million.
It is only your assumption as James Wynn possibly registered his account from a referral link or did not use any referral link. He was also possibly invited through a referral link by someone but perhaps he did not register his account immediately from that link. Later when he made an account registration, he did not use that link.
I agree with you about good chance of getting good passive income from referral links but surely the chances are not too high.
I don’t leave my referral links anywhere because I don’t have a big audience and honestly don’t believe I can make any money from them. Of course, it’s great if someone gets lucky with a high-roller referral, but for most users, it’s not a reliable way to earn anything.