This is balanced out by the psychological good of decreasing prices.
I don't think it would
First, you'll never have 5 million bitcoins, nobody will. Even those with large amounts will eventually sell them to new users as the price increases. Second, there are two options here... if you were actively trading that 5 million, then as soon as the market "realizes" that that money is gone, deflation will occur and prices will take into account the smaller number of bitcoins. If you were just holding that 5 million indefinitely, then nothing has really changed.
I was using an exaggerated example. I was almost assuming that it was a 5 million average, that you would be buying and selling actively with the money.
This idea comes from a fundamental misunderstanding of currency exchanges. Every bitcoin he buys must be sold buy a current holder. As he starts buying up bitcoin, people are going to realize this and increase their selling prices comparatively. Eventually, he'll be paying millions of dollars per bitcoin. This would be a great way for him to distribute his wealth to users of a comparatively worthless crypto-currency. Thanks, George!
True, but he could buy the vast majority of them for not too much money, then crash the system at a time of his choosing, which he has done to national currencies before.
My conclusion, or without currency speculators bitcoin is going down in the long run. It could be a stable currency for awhile, but with no additions after 21 million and accidents causing the loss of currency, the deflation will be really bad. If the total currency supply gets down to a low value, than an accidental discovery of an old HD with thousands of bitcoins on it could rock the whole market.
I mean I like the idea a lot, because I don't like the idea of central banks playing the system like they do today. I just don't think this will be a stable currency in the long run.