How is that inconsistent with the parent statement? Even if the form factors were inevitable--e.g. someone would have decided that smartphones didn't need a physical keyboard--someone had to be first to popularize. (Not sure I agree on the laptop but the iPhone pretty clearly popularized the modern smartphone form factor.)
To say they are "responsible" for something can be read as "allowed to take credit for". Being the first to popularize something is a business achievement, which is quite meaningless compared to the technical achievement of being the first to build something.
Something that's a mainstream business success is far more interesting in general than progenitors that never really took off for whatever reasons. They're may still be important as technical achievements but the history books notice those who took things mainstream.
James Watt didn't actually invent the steam engine. He just came up with an invention that made it a lot more efficient.
I can see this in the case of the PC and the laptop, but proto-smartphones were around for years before the iPhone and they were not developing in an iPhone-like direction. Every iPhone-like product that came after was the result of copying. I don't think it was inevitable at all.
One thing I do think is true is that Apple developed sufficient brand permission to be able to do things that were definitely outside of a lot of buyers' comfort zone and arguably needed some iteration to really nail.
I'm still inclined to think someone would have jumped to a smartphone without a keyboard. But it's also true that the iPhone had plenty of critics early on and arguably didn't fully hit its stride until the 3GS.
