So let's say the price is 1 billion dollars, how many people could pay? If the price was lowered to 1 million dollars how many people could pay, and how much more they make than if the price is 1 billion dollars. If the price was then lowered to 100,000 dollars how many people would pay and how much more would they make than if the price is 1 million dollars? So anyway the price that gets you the most money if you have a product that everyone wants is not necessarily the highest price you can possibly charge ( the price that allows you to sell to say, the top 20 richest people on earth)

Finally, if you charge too much people might just wait for your patent to expire and say we'll pay for the cheaper version later (at the risk of dying from age related disease in meantime)

So, given my age, if there was a cure for most age related disease in the next 10-15 years then I expect that the price would be definitely low enough for me to afford it when I needed it.