No, he's saying that the quality is variable. Sometimes they have one great album and the rest are poor, or an album has a few great songs and the rest sounds like filler.
Well, yeah I guess you're right. But you kinda straw manned me there by changing the subject from an indie band and their work to a general genre. I expect more mainstream bands to consistently be good or bad, but not have the ups and downs I've heard from a couple indie bands. That and it fit my own explanation of how things vary from day to day.
But yeah, you're right, my experience blinded me. And cheer up, your comment seems out of place.
(Serious question -- I don't listen to rock bands, indie or otherwise, so I don't know how the time- and popularity-dependence of their volume.)