Why are most all of the new keyboards flat?

I am a person who types a lot and my preference is the older style keyboards with the big full buttons that make hardly any noise. Why is it that most of the keyboards now are the flat tiny little things that depending on what kind you have make awful clicking noises whenever you type on them? Is it cheaper to make that little piece of plastic, is that why they are all flat anymore or is there some other reason for it?