The problem with this shortsightedness is that if everyone is trying to grab free ram and then drop it as soon as anyone else asks for it, you'll end up in some sort of merry-go-round of applications allocating and deallocating between each other. Or, as per Chrome, swallowing up everything and you have to figure out which tab needs to be closed.

Only the kernel should be grabbing "free" ram and allocating it for cache.