It just became an economical truth. Groups were paying their originals (and sometimes even extra for getting them early) so they wanted "return on investment": a release. What did it take? A team of crackers (or a single cracker) that was always available (24/7). In my opinion, crackers are intelligent people with an "above-average" skillset, which means they would not be your typical audience that lives off unemployment. If they have to be available 24/7, they can’t go to work/school. Conclusion: you pay them (and pay them well).
When the competition increased and 0-minute mass distribution to boards globally became common, every single cracker was getting compensation in some way. It’s that plain simple.