Bitcoin as of now is certainly not going to get out of the hundreds section. I would be so much happier if that were the case, only because this way, we can find a way to control the rising and growing. For example, when it goes low its time to buy. When it's high, its time to sell. If Bitcoin just skyrockets to 400 million dollars one day and just keeps growing, it'll be hard for newcomers to adopt.
There is no real way of finding a way to "control" the growth of bitcoin. In that case, Bitcoin would have to be regulated which is not good... at least in my mind it's not. To have bitcoin "regulated" is saying that we essentially want the Central Banking system, but just with our new nerd toy. Bitcoin is awesome not because it can be transferred anywhere in the world instantaneously (and assuming you can wait a little bit for confirmations), but rather that it is not necessarily controlled by anyone. This is actually up for debate, because now we are having a problem with mining centralization, regardless if no one wants to talk about it or disregard it.
Also, if Bitcoin were to be worth a stupid figure like 400 mil, then there has obviously been an economic collapse of all fiat system and the world economy is in ruins. There will be no need to "cash out" into fiat, because you would essentially be cashing out for shit paper that can't buy anything.