Why do you care about his appearance so much?
The hyper-successful tend to wear what’s comfortable and focus on being hyper-successful. Steve Jobs, George Lucas, Stanley Kubrick, etc - the list goes on - all cared little about their appearance (in your terms), often unshaven and always wearing the same bland outfit. Jony works in a machine shop all day, so the appropriate outfit is a gray t-shirt and jeans and shaving only when stubble gets annoying; dressing up to impress you derails his thought process.
Methinks you don’t understand how utterly obsessed such people are. Changing mental gears to dress up is a problem when you’re juggling million-dollar thoughts all the time. Changing his outfit is, in a sense, lying: anything other than his daily norm attire isn’t who he is.
The issue is how someone cares for their personal appearance. You say that other people dress down; sure they do! What if all the the successful software engineers wore only their underwear?
Well, they are, on top, anyway. Hence, this thread.
Earlier I made the comment that dress revealed the respect that you had for your audience. When I do public appearances, which I do, I dress properly. Next month will be a coat and tie appearance to a group of about four hundred people. Am I wrong for dressing up for my audience? Or, should I tell them to stick it; I’m dressing how I want to because my ego demands you accept me as I am?
Tell me, would you think any less of a person who dressed in a nice shirt, possibly with a tie? Or, does the T-shirt thing get your gears turning?