I'm sure part of it is that Steve Jobs actually understood programming (even if he wasn't a programmer himself) - coupled with his desire that things should be beautiful.
He said that it was a mistake only taking the GUI to Apple, and he should have taken the whole Smalltalk environment. This in turn lead directly to why Next (and hence Cocoa) uses Objective-C. The fact that he would argue with Eric Schmidt in a car park about the merits of why Obj-C is a better O-O language (http://www.businessweek.com/magazine/eric-schmidt-on-steve-j...) says a lot.
He said that it was a mistake only taking the GUI to Apple, and he should have taken the whole Smalltalk environment. This in turn lead directly to why Next (and hence Cocoa) uses Objective-C. The fact that he would argue with Eric Schmidt in a car park about the merits of why Obj-C is a better O-O language (http://www.businessweek.com/magazine/eric-schmidt-on-steve-j...) says a lot.