You're right about the time line in regards with Sony's commitment to BluRay via Playstation 3, setting a precedent for optical disc introduction via PS2 and 3, Blu Ray was the major cost, costing Sony $100 USD per unit because they couldn't get a sell through price consumers were up for as Panasonic learned some years before with the original 3DO (Goldstar, now LG, made their own version of 3DO hardware)
$599 I believe was the original SKU retail price.
Nearly a year after Microsoft Xbox360 with plain-jane DVD-ROM
What locale are you in where there's no HD retail?
Did you have access to HD-DVD prior? (Xbox expansion drives were oddly supporting non-gaming only)
I'm most happy that BluRay can be used for HD expansion based on it's size I suppose.
With PC's graphics cards offering capability for the new format, I imagine, should be somewhat easier for PC home theater users then those who want stand alone