Display Technology Question

Ok, so I've been thinking about the iMac, and some of the advantages of being a hardware and software company, and I came up with an idea. I don't have any clue how feasible it is, but maybe someone with a little more hardware know-how could chime in here.

Why would you change screen resolution? Two reasons I think. One is to tweak performance vs. detail. And the second is to adjust the amount of screen real-estate you have.

In the current time, graphics card performance has outstripped screen resolution on most tasks, especially with LCDs which tend to have a lower native resolution than a similarly sized CRT.

So that leaves us with the prime reason to switch resolutions on an iMac is to adjust how much screen real-estate you have.

Why doesn't apple instead make all buttons, widgets, menus, etc. scalable via Quartz in the way that icons are currently? So instead of changing the screen resolution. All you do is set a preference slider for how big you want buttons to be. This could be a boon for those with poor eyesight as it allows the OS to scale to any arbitrary size.

But the real advantage in this, as I see it, is this:
Currently, both the LCD, and the graphics card have hardware to support multiple possible resolutions. But If you knew for sure that the LCD was always going to run in it's native resolution, none of that would be necessary.

This could potentially make the iMac less expensive to manufacture since the LCDs would require less circuitry and the graphics chip would require less transistors.

Thoughts?