I think if Bitcoin some day hit $1m it won't stand long in that level as every holder would like to cash out his earnings (As any millionaire would do) and thus the price would decrease almost in time.As usual,media would start talking about it's huge pump (and potentially spread fud as we are used to),at that stage fiat currency would see a big decrease in value too.
But meh,I don't think countries will let Bitcoin go that far,if you know what I mean
It is very unlikely we are going to reach the price of one million anytime soon, if the price reached 40k or 50k people will begin to cash out, so bitcoin will not have a chance to even get close to that price, now that does not mean that the price will not be reached at some point in the distant future but people need to stop dreaming those prices will be reached soon and even if it did that will be a sing that something is terribly wrong with the economy and I will have more things to worry than the price of bitcoin.