Explain to me the concrete dissimilarities of Desktop OS, Server OS and Mobile OS?

With the introduction of the new iPhone last week, the conversation inevitably turns to the debate between iOS and Android...and that conversation often leads to the question, why are there no new mobile operating systems?...take a look at the following video:

https://www.youtube.com/watch?v=-N80hzTpglQ

There are many compelling reasons given as to why there are only 2 main mobile OS and how those difficulties can be overcome...

So what do you think?...do you agree with the video as to why there are only 2 main mobile OS?...do you agree with the difficulties concerning introducing a new mobile OS?...what about those ideas on how to introduce a new mobile OS?...

Pick at least 2 ideas from the video that you agree or disagree with (you may select more if you wish) and explain why you agree or disagree...you may use personal experience or provide links to other reference material to support your opinions...

Remember...your ORIGINAL POST must be 3 to 4 well-structured paragraphs and your TWO REPLY POSTS must be 1 to 2 well-structured paragraphs...you cannot simply "agree" or "disagree" on a REPLY post...you must given reasons why...and be sure to give credit to any sources you use in formulating your replies...