He is right
I was sorta kidding. Making fun of "do it all producers" that seem to be popping up everywhere these days.
"I'm producing, recording, mixing this entire record, and writing drum parts, then actually playing drums and bass on the album! Who cares who plays bass on the record anyway?"
Good thing for mixers like us though, is that a lot of people do use a mixer who didn't record the material. I think it brings a lot to the table, unless your mixer sucks...then, well, you've got problems.
Me personally, I'd much rather mix than track.
I'm willing to bet in a few years the A&R guys will start mixing records, maybe mastering too...haha!