I'd disagree with that. Looking at how messy my keyboard is I could only imagine how messy a monitor would get with my greasy fingers all over it.
In addition attempting to type anything of great length or quantity on a touch pad would be a nightmare unless of course it was the size of a traditional keyboard. But still believe it'd be pretty difficult.
The touchscreen on a phone is admittedly pretty cool, however unless something comes out that makes it practical to use I couldn't see the technology really taking off on the PC.