Most of them are either admins (read: global moderators to enforce site wide policy) and “community builders” that spam subreddits with reposts and junk to boost activity. Some of that spam was malicious bots of course, but a lot was also from reddit themselves. That’s why the site appears as active as it is with so many content creators leaving.
Their development team is probably very small.
70 quits. Around 4,000 would be needed to break encryption. This is a step in that direction and still a huge achievement!