Why are you comparing cars with phones?
Even the laptop processors are only 60-70% powerful to a 100% powerful same desktop processor.
Gaming consoles are much underpowered than a high end desktop graphic card, which results in the graphics output. It's because high end GPUs need much power to work. They uses outdated GPUs instead. So they offer mobility.
It's not possible for a smartphone to come with an i5 or i7 processor with a 2000-3000 mAh battery!
Jayadev, when did I say it's only the clock speeds which gives the power??
Edit: "But beware that a dual core desktop processor is miles ahead than a quad core mobile processor." is wrong, sorry for posting the wrong information.
Quad core processor is better.