This is purely a guesstimate but I presume Mastodon is in the top 10% of open source projects, in terms of user numbers. It's sitting on a goldmine of contributors - this user base skews techy, after all.
I don't just mean developers, either. There are loads of UI and UX designers here. People who could be doing the research on and designing what people want to see here on Mastodon.
People who would save the Mastodon team from stumbles like they've just made with the Unlisted renaming.