I see what he means. Commodification does reduce meaning and value.
I guess I see it as a "glass half-empty vs. half-full" thing. Since greater access leads to quantity, average quality will go down: you have an influx of music from non-professionals, vs the less-music-but-higher-quality era when making music required a lot more skill.
I'm not convinced, though, that ultimately, that's a bad thing. I look at it the other way: quantity broadens the surface area for artistic innovation.