Serial was ubiquitus but hardly universal. Loosing hours to the "change the baud, bits, reboot it" dance whilst bit-banging cts by shorting things with resistors, all just trying to get a terminal. Mating wildly different number of pins, pinouts and connector shapes whilst being mindful that some devices want -48v and others between 3 and 5, it was a frikkin' mess.

Lots of problems; big mess. So they unified things to a universal standard, whilst still keeping the spirit of serial alive. And by that, I mean wildly different plugs, different numbs of pins, incompatable pinouts, crazy voltages, drive issues and more. Truly the interoperable future is here.

(what? no, pass me _the_ usb cable. Idiot; it's the one that looks like the inside out apple cable. But not _that_ inside out apple cable, because although they're identical on the outside and will plug together....)