I have been an email administrator for an ISP and a University, and I have been active in many spam related forums/mailing lists for many years now, and I completely disagree.

Blacklists catch far more spam than bayes, are far easier to administer and far less resource intensive. Personally, I try to deploy both, with blacklists first in line, then bayes to catch some stuff that the blacklists miss.

"Sender authentication" is a vague term. If you mean verification of the sender address via various DNS lookups, then yes, that's quite useful, but still nowhere near as useful as blacklists.

This is how I see people setting up their spam filters in the industry. It might not be idealistic, but it is effective and wide spread.