Perhaps, it takes up too much real-estate and/or costs too much at the silicon level? However, I do remember when some of the socket manufacturers had sockets with built-in bypass caps...ok, i'm just hoping: why can't they just build that into every ic then..
Yes. I remember looking at a picture of the old 741 chip, which has a 30pF capacitor on-chip, and the capacitor took up a significant amount of the total chip area.If I remember correctly, capacitors are the biggest component to create within an IC?