If US Dollar crashes then Bitcoin price will go very high and people already holding it will make money.
I have to disagree sorry. Every decade or so a national currency crashes and its
people are made poorer generally. Money does serve a purpose, a utility and some work is saved by allowing that convenience and ability to save.
IF that system is destroyed, generally losses occur. I agree prices will go up as the dollar worth goes down, its true but overall the effect makes people poorer as confidence falls and uncertainty means less trading
I also have to disagree with your approach
If I got your point right, to begin with. Basically, you mean to say that people holding dollars will become poorer overall and they won't be able to buy bitcoins therefore Bitcoin won't shoot to the moon. Obviously, you fail to take into account at least two major things. First, whether the majority of people becomes poorer is irrelevant to the price of Bitcoin (however cynical it may look or sound) since Bitcoin is only used by a small percentage of people (and only these matter). Second, people may become poorer only because of the dollar losing its purchasing power. But if they don't have devaluing dollars (apart from what is required for everyday expenses) and keep their wealth in something else which will preserve its value, their impoverishment will be negligible. So we have two groups of people, the first is using Bitcoin, the second consists of wealthy individuals. In reality though, the second group includes the first (i.e. it is wealthy people who are using bitcoins). If the dollar starts to crash, they will be trying to get rid of their dollar stashes as soon as possible, but since the dollar can't collapse overnight, they will evidently front-run inflation. And where wealthy bitcoiners will pour their dollars into, in your opinion?