I was more thinking about normalization of walled gardens in personal computing devices and resulting duopolisation of the market. Widely used mobile Internet, social networks, touchscreen smartphones were coming with or without Apple, and it's not like the carrier-dominated market was all flowers and butterflies otherwise, but ultimately it was Apple who used its market and cultural position to push non-interoperable stuff like iMessage, fight "jailbreaking" and "sideloading", gatekeep software availability etc. which defined the course of action in the industry for the next decades. These things aren't what made iPhones successful and it didn't have to be done this way.

There was no “wall garden” with the iPod. In SJ’s “Thoughts on Music” that he posted on Apple’s front page in 2007, he said that less than 5% of users music came from iTunes.

This was the same post he said he wouldn’t license Apple’s DRM. But if the music industry would license their music DRM free, the interoperability goals would be achieved an Apple would sell DRM free music.

One of the major record labels and some independent labels took him up on it immediately. It took two years for the rest to come onboard.

iMessage always supported SMS and now RCS. What more did you expect Apple to do?