Software upgrades have been provided long by Microsoft. Just like may other things, Apple brought it to smartphones. Because smartphones are more like computers than phones. And strictly speaking, Nokia also released upgrades long before Apple, though they were painful to install.
BTW even if we assume for a second that the concept of upgrades was Apple's idea then by now Samsung, HTC, LG, Google and every phone company in the world would have been sued for upgrading their OS.
And Apple doesn't believe in giving gifts to mobile industry. Unless you call legal notices gift :)