Wait. Blogs posting a few times a day at most? I think their definition of "blog" is now closer to a news website. Overall there I'd agree that quality has gone down - it happens anywhere there's substantial money to be made. But I have more personal blogs than I can keep up with, and most of them are what I'd call extremely high quality.
I don't think there was any "mind" that kept quality high and volume low. Volume was just lower, and there were fewer interested parties, and they were less motivated by money (because there was less money to be had). There are ridiculous quantities of excellent lower-volume "blogs" though, you can hardly call them dead because you're using the populist channels to try to find them. Is that how you found them in the 00s?