What are the pros and cons of each? And are desktops really being phased out like I keep getting told? I want to build a gaming desktop and can get all the parts I need for around 1.5k, which would cost over 3.5k in a custom laptop, and my parents want me to get a generic laptop which can just run Microsoft and Internet, because desktops are phasing out and people are going smaller(which isn't true, iPad is younger than itouch, iphone 5 is bigger than others). But if I can see the pros and cons of each, then I can see if I really should just get a laptop, or if self built desktops are way way way better, then maybe I can convince them to let me build it.
So basically, pros and cons of self buit desktop vs higher end generic laptop. And are desktops really phasing out?