The first cellular phone in modern currency cost something like $15,000. At that price, the market for it would be orders of magnitude below the present cellular phone market size. Lower the price 1 to 2 orders of magnitude and we have the present cellular phone market, which is so much larger than what it would have been with the cellular phone at $15,000.
Interestingly, the cellular phone market also seems to be in a period where competition is driving prices upward through market segmentation. This is the opposite of what you described competition as doing. Your remark that the real world is more complicated could not be more true.