This is a good question for two reasons:

1. Copy-paste is an ubiquitous operation,
2. If you think about it, this is the same problem that is currently happening with touch devices. You have a hard time figuring out that you can use a 4 finger swipe to do an operation, but once you learn it, you become much productive.

This means that everyone will be performing this operation, but new keyboard users will have a hard time learning the operation.

The problem is (as BlueFlame pointed out), that the are several frequently performed operations. If you had a dedicated key for each one of them, your keyboard would be huge. This would mean that you were decreasing the learning time for operations and increasing the learning time for the keyboard.

Fitt's Law

Also, there is another think to take into consideration: Fitt's Law. Dedicated keys make the keyboard bigger, this means:

1. Distance from regular key to special key increases
2. Distance from mouse to special key might increase

Form Factors

Another think to take into consideration is that nowadays you have lots and lots of form factors al using the same keyboard (QWERTY). You can argue if this makes sense or not, but the truth is that no one finds it fun having to learn a new keyboard for interacting with a single device. Remember Nokia's keyboards?

So, hardware and software designers are still trying to figure out ways to make you productive, while ensuring that you don't have to learn a new keyboard for each device you own.

Well, there's the True X-Mouse Gizmo, if that works in your Windows version (it's a bit dated).