Voicing s as /z/ is widely variational. For example, I voice the s in "us", and "Muslim", while others don't. While I don't voice the s in Australia (/ɒ.ˈstreɪ̯.li.jə/ ~ /ə.ˈstreɪ̯.li.jə/), I do in Oslo (pronouncing it /ˈɒz.loʊ̯/).
Look at Jony's designs, everything from the first iMac to the soon to be released Mac Pro can be boiled down to a rectangle with rounded corners. 20 years of the same core element has caused it to become stale.
Or maybe just maybe market decided that this was actually the best form factor for computer so far? Maybe also not unrelated to the fact that screens are rectangle...
You can’t blame Apple as it’s one of the few company that actually tried alternatives... that market rejected.
To name a few : the twentieth anniversary Mac, the "Luxo" iMac, and more recently the trashcan MacPro