What is the end goal price?

I see two problems with Bitcoin or any cryptocurrency for that matter.

One, how can we use it as a currency if its value is unstable? Bitcoin price goes up and down so much that it is basically a failure as a currency. Imagine if the US dollar losses half of its value 6 months later. The entire financial world would collapse and people would have no means to trade except with sea shells and gold coins.

Two, what exactly is the end goal price for bitcoin in order to be a stable currency that everyone can use with peace of mind? Is it 1 million dollars, or 20,000 dollars? Which one is it and how can we ever settle down for a price we all want?