OK, realistically this may happen but it is years away from being a reality. The winners in the tech world are the ones who can foresee how something will pan out in 10, 20, 30 years, thats why IBM sinks as much into R&D as Intel makes in revenue.
OK, the ask here is to imagine that all your processing is done by fat servers in the Cloud, including all your gaming as well, all your files are stored in the Cloud too and the wirless broadband speeds are up in the 50mb range.
So at home you basically have nothing more than a thin-client dumb terminal connected to a monitor, so what's to stop the monitor and keyboard being connected to your phone instead? Once you farm off all peripherals to a docking station including DVD, monitor, keyboard, mouse, printer, speakers then your PC, or laptop, or smartphone is nothing more than a fancy way to connect to the internet where all the hard work is done. So it's not so unrealistic, timeframe is the factor here, not if but when.
I'll give it 15 years.