Replying to andrepd's comment to your comment:
The incredible amount of Work, Capital Outlay, Engineering, etc.etc.etc. that is required to create mobile phones is a huge barrier to any group of people doing so. Therefore, they are incentivized to generate a profit on each phone they eventually produce/sell. If the phones are popular enough, then they may make quite a lot of money. Like jesus dude, nobody forces anyone to buy a phone - everybody is doing it of their own volition and that's why mobile phone developers get rich.
