Online Store: Why no option for third party keyboard/mouse?

Why won't Apple allow their customers to purchase an iMac with a keyboard and mouse that's not from Apple?

Or allow a customer to buy an iMac without a keyboard and mouse which should result in a savings of at least $50?

Why???

What's wrong with wanting choice?

Okay, I understand it is their store and they can do what they want. I also know I can do what I want and buy some other computer, but shouldn't Apple cater to their customers with more choice?

I'm not saying they should change the look or function of the iMac or the Mac OS. All I want is the option to have an iMac without a keyboard. This would be especially useful for someone who is upgrading from an older Mac.

I still think the lamp style G4 iMac was the best iMac design. I wish they would reintroduce that.