The first iPhone didn't have anything. In terms of features it was laughable and it could barely be considered a smartphone. It succeeded because it was a phone on a touch screen that worked better than any previous attempt at touch screens.

Everything that made iPhone relevant against Android only came out later. Apple had a large quick start on hardware and UX, Android had a large quick start on the feature set. They both worked to close the gap and now we have two very similar products.

Microsoft didn't have that gap with Android on the OS level in any way. It could do everything. But they didn't have apps, because the devs didn't want a third OS to exist. Devs who just wanted to expand their customer base were making apps for wp just fine. Companies who wanted to manipulate the market into what was more convenient for them did not. Regular folks were making apps to get YouTube, Snapchat, Instagram and that sort of stuff working on wp just fine - someone even made a Pokémon Go client that actually worked on windows phone, but the companies behind those platforms actively wanted those apps to not exist in any way.