Just the other I realised Jobs was right saying the size of the iPhone was perfect because of human thumb size, his mistake at the time (assuming he really thought this through and wasn't just being a salesman) was to think consumers would always value the ergonomics above everything else. In time, even Apple realised consumers were probably favouring other things like the screen size itself even when ergonomics suffered a lot with it. It's a very important message right there for any one size fits all strategy.