Exactly . . . it's really not about the hardware, it's about the productivity of the applications . . . now Apps. For instance, just as the iPod wasn't the first MP3 player and the iPhone wasn't the first touch screen smartphone, the iPad wasn't the first tablet touch screen device, but it's sensational success is more the result making the connection with the user as a relatively low maintenance appliance instead of a "computer."

BTW. Apple does upgrade software and issue security patches from time to time, but historically not as often as Microsoft.