One advantage of doing things this way is that it makes it easy for people to step down when they've had enough.

It's a pretty low-traffic and low-turnover group in Django. I've done it four releases in a row, for example. When there's only one feature release in most years, it's not an issue at all to do a quick call for volunteers. In Django's case, often there's not a real need for an "election" since you only get as many volunteers as there are spots on the technical board.