Firstly, what if someone lives in Africa/Australia and the stock cooler gets too high temps? Also, overclocked, not very well cooled chips will die a lot quicker than not overclocked adequately cooked chips. Also have to factor in decent case airflow, which by the way is hard to come by in budget builds, and the fact that Intel Stock Coolers are OBNOXIOUSLY loud.
I have an I3 4150. Even with hyper threading, I am at 98% usage with Chrome, Skype, and Minecraft. That is LIGHT multitasking and I am there, and remember Minecraft is single-threaded so it does not even occupy all cores.