When MS was any kind of notable player in the smartphone/smart device marketplace, it was an incredibly small marketplace. Honestly, other than perhaps acting as some sort of inspiration for Apple, I don't think it had substantial influence on what came later. And frankly, I think the Blackberry was probably a much larger inspiration.
Ultimately, Apple learned a lot of useful lessons from the monster success that was the original iPod, and then saw how those lessons could be applied to a smartphone. RIM and Microsoft released mobile offerings that were functional, could run a wide variety of software, and certainly had some penetration in the enterprise, but Apple made sure iOS wasn't just a business workhorse (in fact, I see little evidence that it gave a damn about the enterprise at all), but rather a very consumer friendly device and then marketed it with astonishing brilliance. But at the end of the day, Apple's success with iOS is down to the original iPod. It gained its killer product, and built the iPhone and the iPad on the same premise.