Ok, how bout this for a reason why not then.....
USB 2.0 has throughtput of 480Mbit/s, right? Well, lets say you get have 6 usb ports on ur rig. they all share that on the internal hub. Who cares if you can connect multiple cables? U can reach the limit on 1 cable.
now lets say you add a whole other controller... well, at that point. good luck (just buy SCSI)
I'm a NO guy.
Optimize ur device, dont reengineer it. unless u r that bored