Why are newer models cheaper than older ones?

[jpthomas27]

I'm almost ready to purchase a new plasma and am pretty sure I'm going with a Pioneer. What I can't figure out is why the 2008/09 models are cheaper than the 2006/07 models. Shouldn't the older models be cheaper?

Here are the comparisons as far as MSRP is listed. The actual retail prices I've seen seem to follow the same pattern.

Pioneer Kuro
(old) PDP-6010FD = $6,500
(new) PDP-6020FD = $5,500

Pioneer Elite Kuro
(old) Pro-150FD = $7,500
(new) Pro-151FD = $6,500

I've read everything I can find on all 4 TVs and I really don't see much of a difference in any of the technical aspects. I haven't read anything that really indicates the Elite Kuro series has any better picture than the Kuro series either.

Are the older models really better?
Are the Elite Kuro models worth the extra money over the Kuro models?

Any help clearing up the confusion would be most appreciated! Thanks.