They won't be able to get the money if they only think about money but they have to think about the people they have invited to join. Usually, people will be interested in joining if there is attractive compensation, so they will voluntarily join and deposit their money. I've heard that some people spread their referral links on social media and offer that people who join them will be given some money, which makes people want to join. Maybe it's a strategy that some people out there continue to attract new members.

If they have been successful with that method, they only need to keep an eye on the amount of the bonus, which might immediately increase sharply because they have shared some of the profits with the new people. They may successfully spread the referral link if they pay attention to this.

If they also spread the link of scam casino and will not care the consequences of their action then chances for them to get scam is also there. This is a total waste of their effort if they only think about theirselves knowing a casino can hold their earned money if their accumulated referral commission is so big. So Better if they could just play fair then promote the legitimate casino so they can earn together with they can assure that their referrals are safe from scams.