[Q] On the topic of Idling

It is my understanding that the best way to acquire TF2 riches is by idling. I have a few questions. 1) Is it really the best way? 2) How does one use other accounts to idle? 3) What is net gain of idling? 4) Why is this game so consuming? 5) How did Valve manage to make us pay 60 dollars for virtual hats in a game? (Don't answer the last 2, rhetorical)

Thanks for your time, mentlegen.

EDIT: By "Pay 60 bucks for a hat," I meant unusuals.