Computer desks have evolved very nicely as computers have changed. The first computer desks had huge superstructures attached to them so as to accommodate bulky printers and hold cathode ray monitors. Because of these monitors computer desks had to be very deep. It was not uncommon just 10 years ago for an office desk built to hold a computer to have a 4 foot depth.
Obviously this used and wasted a great deal of space. New flat screen LCD monitors are far larger in size. They are also much thinner. This allows the monitor to be placed further back in position on the desk and yet still be seen. The computer desk we purchase today is narrower and returns to the conventional office desk appearance. A major change is that desks today have rounded edges. We tend to get up more from our work areas and need to not catch a leg on a pointy corner.