If I purchase a Cable or Satellite Box, I dont get to choose which software controls that box. If I buy a TV set, I dont have any control over the remote control that comes with it. Suppliers determine their packaging.
Your satellite receiver analogy is weak and irrelevant to the issue we're discussing. You might as well complain that your floppy disk drive requires floppy disks and won't play DVDs.
Dell computers are general purpose devices that do not have any physical design limitations which would prevent them from shipping with no operating system installed.
The reason the OEMs are buckling on the "naked PC" issue is because - figuratively - Microsoft has a gun to their heads. They would be happy to sell naked PCs - but if they do, Microsoft will raise the price of their Windows OEM license to the point where they can't compete with manufacturers who capitulate to extortion.