That's certainly part of it. The graphics hardware is the other part.
Most people are so set on a big display, they don't notice that the pixel density is low and the graphics hardware is unable to display 3D or video with any decent throughput.
A lot of LCDs just don't have the colour gamut to display 24-bit images correctly, let alone 48-bit images. Of course, most people making their money at graphics work should be buying monitors that cost as much as their laptop computer to ensure colour fidelity, yes?
Thus I think desktop still better.