Also, the maxim "don't trust, verify" really does apply.  Even the most popular, most-supported or long-established contributors can introduce bugs into Bitcoin Core.  More eyes on the code -- more independent review and testing -- is needed.  This is the true, key role.

jonatack

bitcoin

Jon Atack AMA

Maybe that it doesn't involve writing code so much as reading and reviewing/testing and also mentoring/education. That what is most lacking (and perhaps needs to be incentivized more/better) is experienced and constructive review.