Those pricey displays were more marketed towards the medical industry for the 200ppi. Its high resolution also required TWO (or more?) video cards to drive.
they were great, 15 yrs ahead of their time, and are are still about on EBay, The T221 DC5 is the best and last version, but...
they have a quite restricted Gamut compared to modern monitors. (I have an icc profile for one somewhere), as it wasn't made for colour pros, but for technical design, nobody looked at the colour range much.
they also require a special card to drive , e.g Matrox makes one (its $2400)
they do NOT work off dual link cards, or even dual-dual link cards.
At the moment the best we have is 30" displays, though hopefully someone will move to at least 150dpi 30" monitor running from a dual dual link card soon.
I think the failure of the T221 (IBM lost a fortune on it) has scared most manufacturers away from ultra high res displays, though hopefully this will change.