Sure, MS launched PDAs and phone-ish devices long ago, running Windows CE and whatnot but they were awful. It's absolute bollocks that the iPhone was a splashing success because of Apple marketing. It was a splashing success because it worked spectacularly well. Random non-tech people would randomly pull out their newest purchase to show their friends. "And now it's a notepad!" "Look and now suddenly it's a calculator!" Sure, your awful HP Tablet had all that, and a call function, well before. But it sucked. It felt like using a computer while squinting, and not like a magic calculator that can turn into a notepad and then into a phone and then into an iPod.
The iPhone was a success because it worked so well. And it worked so well because the technology was there - in part because they invented it and in part because they had the taste to not bring out a shit product but wait a bit instead.