Does it really take much to maintain a user modifiable tower? I imagine the amount of engineering the 2013 Mac Pro took, was greater than simply maintaining a 4

Does it really take much to maintain a user modifiable tower? I imagine the amount of engineering the 2013 Mac Pro took, was greater than simply maintaining a 4x PCIe slot box with whatever the latest and greatest Xeons are. Apple could have left the tower exactly the same. Problem solved. It's not sexy, and its not exciting but it'd keep a very dedicated group of Mac buyers happy and married to the platform. It isn't mutually exclusive to cater to both audiences.