Why no WD, Seagate, Hitachi, etc. SSDs?

Seagate (Pulsar), Samsung (470), Hitachi (Ultrastar) and WD (SiliconEdge) have SSD.

Pyree, you got me there! I knew (and forgot) about Samsung-- I think they've just come out with a second gen SSD called the 800 series or something? Didn't know the other biggies even had one though!
I guess that's the thing, aside from Samsung (and I'd already forgotten about their SSD, having read about it only once, and never seen it advertised anywhere), I'd never read anything (on this site or any others) doing a comparo, selling, or even mentioning any of the other big HDD mfgrs.
Crucial, OCZ, Adata, Kingston... granted, all those are already in the flash memory business, and would theoretically have an edge when it comes to packing memory into little plastic boxes and calling them hard drives, but still-- if your bread and butter depends on it, I'd think the big HDD makers would have more (and faster, and more economical) horses in this race. Plus they'd theoretically have a leg up when it comes to building & ensuring universal compatibility of the boxes that hold information, regardless of the physical means of reading/writing/storing that info.
Ten years from now, I can't envision the standard, motorized, whirring HDD having any place in any system, aside from my cr@ppy work PC, which will only be upgraded when a serious lightning strike burns the office to the ground. At that point my IT department will sift through the ruins and gob together yet another Dell Dimension 2400...

They don't. They don't have the controller for the chip and they don't produce the NAND flash in it.

The only thing they have is really just the enclosure. But even that won't fit the silicon in because the mechanical HDD has space for spindle, motor and head etc not a smooth box for the SSD chip to put in.

Therefore, they don't have any edge.