well part of my issue is that there is a huge gap with all the common monitors being stuck at 70 to 90 ppi in general and so few "desktop" displays that go past 90ppi.
300ppi is a "nearly ideal goal" for having displays where we stop even counting the dots and just enjoy it.
but in the mean time I would like to see desktop displays that are more than 100 ppi be more common. in laptops they do it, why not for a desktop screen ?
You do know that "retina" isn't based on ppi, right? It's a fuzzy term invented by Apple that means "you shouldn't be able to perceive pixels at a normal viewing distance". A "normal viewing distance" is not specified, and is going to vary greatly depending on the device. The 15" MacBook Pro retina display has a 220 ppi, for instance, not the 300 ppi of the iPhone retina display.
Wikipedia has an equation (http://en.wikipedia.org/wiki/Retina_display) you can use to try and guess what a "retina" desktop monitor would need in terms of ppi. This SO question does a slightly better job (http://stackoverflow.com/questions/12593936/what-is-the-formula-to-determine-if-a-screen-is-retina-resolution). At 24" (many computer desks I've found in a quick search have 25.5" depth) the ppi is only 143 for retina displays. The "normal viewing distance" is probably less than this, but more than for the MBP. I'd guess probably around 180 ppi, but I'm just guessing, since that magical "normal viewing distance" isn't specified.