I think he means that good speakers are more important than good amps for SQ. Not the dependant on the listener part.
EDIT: And I REALLY should pay more attention to stuff that's in bold. Really. I feel stupid now. But it's late, so whatever. =p Relative SQ is listener dependant, Absolute SQ is measurable.
And I agree. I happen to own a pair of high quality speakers (Rainbow) and low quality speakers (Boss), along with a high quality amp(PPI) and a low quality amp(Jensen), both pushing within 10 watts of each other (RMS).
Good speakers + good amp = good SQ
Good speakers + not good amp = good SQ
Bad speakers + good amp = bad SQ
Bad speakers + not good amp = bad SQ
100% experienced by me, equal installs, ~equal power, different equipment.