With this logic lets apply it to a hypothetical situation. You're hundreds of miles from the nearest town and you've got a flat tire. You don't have enough water to make it back walking and you are relying on someone to give you a hand. A person comes up to you and sees you are desperate in this situation and decides to take advantage of you and is willing to sell the tire for $5000. You refuse and say its outrageous to think anyone would pay $5000 for a tire. So he leaves, and you say well someone else will be along to sell me a tire for cheaper. Here's the problem, what if nobody else comes around OR if they come but it was to late.
That's where the drug Daraprim comes into play, company buys the rights and hikes the price 5000% overnight. Sure, maybe in a few years another drug will be out that does the same thing Daraprim does and is a lot cheaper. But here's the problem, it's going to take more than 2 years for the new drug to be approved. So in the meantime this company is going to make BANK off this drug and if you can't afford it you're going to die or somebody else is going to pay the bill(omg free stuffz). Oh and I almost forgot to mention this same drug costs practically nothing in other countries like Canada and the UK.
