There was also Tizen, FirefoxOS and a whole slew of others. It was a remarkable time.

But it is true that the app-based future, that didn't exist yet, probably came with market dynamics that limits the number of platforms to two or three. It just wasn't clear which those were at the time.

What a vanilla Linux-based platform, and Meego, Maemo, Moblin and Mer were just iterations of the same thing, would have had going for it was that it could have had much better long time support and not just for hardware for software. Linux famously do not break userspace, and can regularly run 30 year old applications. For a phone you would be surprised if a 3 year old app worked.

Microsoft did this so much worse than both Apple or Android, even if they all suffer from it. Every release of the operating system came not just with new design language, never earth-shattering but often interesting, but new GUI toolkits and application packaging. Just a recompile of your application often wasn't enough, you were expected to rewrite your application to fit in with the new. They really shot themselves in the foot with that, and they did it over and over again despite never having leading market share and everbody seeing where things were heading. It was (and perhaps still is) probably the only way they could operate as a company.

The vanilla Linux-based platforms mentioned above had their own problems which should be obvious from the naming scheme alone, which would have compounded had their marketshare grown bigger. It was a forkfest. But that's the issue with corporate open source, there is rightfully an inherent skepticism where a single company dominates what is an open source project. This is also why Linus never took a job with the big Linux providers. It wasn't for a lack of opportunitites, but he knew that had he worked for Red Hat, people would always suspect even technical decisions to be made for the benefit of his employer. The most successful open source projects are vendor neutral. That is not in telecom companies culture, they had a very hard time understanding that and tend to form alliances instead. Not the same thing.