Earlier quoted context omitted.
I bought Samsung Galaxy S3 recently, plugged it in via USB and was not able to browse it because, as far as I understood, MacOSX has no support for "media devices" whatever that is. I had to download some obscure Samsung "Kies" software through which I was able to get to the filesystem and upload some files. Wasted hours.
Oh my This is 100% to blame on Samsung, sorry. Even though my Samsung phone is seen as a USB device (and it works on MAC OS X), but maybe in the newer models they removed this functionality (and called it a feature) People may complain that iPhones need iTunes but then again it's iTunes not the gigantic pile of crap that is Kies
It was pure engineering tradeoff to improve things in the long term. If anything OEMs would have preferred the old 'just works', sub-optimal, gives-an-excuse-to-obsolete-a-phone, lower support issues, solution. The ball is now in operating systems' court to support this standard in a way it wasn't envisioned to work a few years ago.
Even ubuntu has been slow on this front.