Even in a best-case scenario ($100 drop every year which would be insane) the PS3 price will still be:
$499 in 11/07
$399 in 11/08
$299 in 11/09
$199 in 11/10
$99 in 11/11
So it won't reach a mass-market price 'till late 2010 and won't hit $99 until late 2011 when the next gen will probably be starting if not the year before. Price is going to hurt the PS3 for the entire generation.