They should also review the code.
Test changes
Make pull requests
Delegate all their stake to communities
Fight spam
Running $1,000+ /m full node
$500-1,000+ witness cluster
Test on test net
Provide witness server for test net
Be available 24-7 for outages
Do all nighters for hard and soft forks
Answer witness surveys

All for $36,500/year (which isn’t even liquid) as a top 20 witness. I’m #30 and make 1/8th that.

Just to put in perspective, a blockchain dev that is capable of reviewing code and making patches is worth $100,000-$250,000/year if all he did was code.