But the other thing is quality. Viewing angles and color gamut tends to be horrible on laptops. Not so on the iPad.
I'm still sad that even the MBP 17 comes with a 6-bit PVA panel. It's a nice panel, but dramatically inferior to an 8 or 10 bit IPS.
It all makes the IPS panels in the iPads even more impressive. From what I've read the IPS panel yield goes down with DPI, too, so the panel in the iPad (Early 2012) is amazing.