✔ 最佳答案
First of all is your question about mobile phone companies or MOBILE PHONE NETWORK COMPANIES?新世界傳動網, 3和記 are not producing mobile phones man...
Mobile phones market is what we called Oligopoly. There are usually 5-10 dominating firms within the market and they are price setters, rather than accepting general market price. This is why they are highly profitable and therefore being more established than new entrants which leads to a further dominating power.
Apart from the above issues, there are also a few characteristics of the market structure that prevent new firms to entry: try to talk about some issues like:
brand image - why somebody might prefer buying mobile phone from one particular brand, say, Nokia than others despite a higher price?
High sunk cost - say, if you want to establish a new firm that produce mobile phones there are high costs in setting up machineries, and also lack of technological research about new phones(other firms might be far from you in the front about this)
Probably the most important argument is that existing firms are having a greater economies of scale therefore better established. They have higher capital funds and the ability to cross subsidize their loss on a few products hence they can push their price lower in order to enhance price competitiveness, which a new firm might not able to do so.
For example, Microsoft and apple have entry the mobile phone market since 2005, at first they might face a loss by not achieving expected sales due to lack of brand famousness in the market and also huge advertisement expenses. However the main thing is that by selling computers they have originally have enough fund to cross subsidize their loss in a short long until their product lines become more mature.
see參考資料 for the market shares,
Regarding to their profit margin and stuffs go to their websites and get an annual report
hope it helps.