The set of people who can verify "yes, that trophy is valuable" is way larger (and less motivated) than the set of people who will sift through the firehose to find those trophies.

That's part of why you see a power law distribution of engagement in any ecosystem.

The "spoils" are "how many people think more highly of you given you found the trophy" and the difficulty is "how much effort does it take to find a trophy".