Box fan cooling (Score 1)

I know this is much of a logical leap, but why not use two very large fans on each side of the case and no small fans inside the case. There is a lower probability of failure because of the fewer components and also an improvement in noise since large fans don't have to spin as fast to move the same amount of air. This system would also likely help keep everything cool including your hard drive(s) and power supply.

So my question is, why haven't we taken this next logical leep?