In terms of interchangeable commodities there is space for many players. But in terms of more fundamental standards such as Windows vs Mac , JS vs Flash , VHS vs Betamax there tends to be one strongly dominant winner. The Mac only became really popular once it basically became a PC with a different GUI. In terms of cellphones pre smart-phone most were basically interchangeable since they were all capable of making voice calls and SMS over GSM , there was limited interest in developing applications for them by 3rd parties.
The disadvantage that iOS has in terms of becoming dominant is that only apple at present makes hardware which can run it (officially anyway) so it is in Apple's interest to keep the hardware cost relatively high since they make allot of money from selling it.
Once the it gets to the point where everybody wants a smartphone and tablet computer there will be allot of pressure for low cost products which Apple has no interest in providing. Android & similar can win bigger here because google does not make money from the hardware. They make money from the advertising etc so they are mostly interested in making sure that there are as many low cost products as possible that can run their software.
I still think if I listed every category of electronics, you could not find a dominant player in the majority of them.
I find it interesting that you ignore Apple's behavior with the iPod. Apple was more than willing to provide a low cost product. I really don't see why people think that trend won't be repeated.
You might not find a dominant manufacturer but you would find dominant standards where compatibility is concerned.
The iPod is an interesting example I agree, but it is still generally towards the high end of the MP3 player market and it still supports the standard MP3 format making is compatible with all the music you already own.
So switching from another brand of MP3 player to iPod (or vice versa) is pretty easy, there's no real case of having to choose.
If Apple had chosen a different audio format for the iPod for example , that meant you would have to buy your music in a format that was only compatible with it then I doubt it would have enjoyed the success.
The only reason the iPod is cheap anyway is market pressure from competing manufacturers. If Apple had per my previous example gone with a different audio format and been the only player in town they would have kept their prices high and it would have become inevitable that a competitor would have entered at some point with a lower cost product.
The only thing that would keep people from buying the competing product at that point would be that all their music would be stuck with apple , making them a defacto monopoly but over time the lower prices of the competitor would either force their prices down or drive them out.
The disadvantage that iOS has in terms of becoming dominant is that only apple at present makes hardware which can run it (officially anyway) so it is in Apple's interest to keep the hardware cost relatively high since they make allot of money from selling it.
Once the it gets to the point where everybody wants a smartphone and tablet computer there will be allot of pressure for low cost products which Apple has no interest in providing. Android & similar can win bigger here because google does not make money from the hardware. They make money from the advertising etc so they are mostly interested in making sure that there are as many low cost products as possible that can run their software.