If 500,000 ever happens I dont feel it will be in a world operating in a positive situation.    500k is possible but not likely without extreme circumstantial changes such as US Dollar collapsed for some reason, maybe China sold all their treasuries and let the value fall to nothing.
Its unlikely to happen any time fast as China would lose money that way but alot of countries are backing up the value dollar which in turn people measure Bitcoin or many other prices by.     If you look at Zimbabwe or Venezuela more recently, any price is possible because the scenario is that no prices matter by that point in time.

   We have democracy and I pray it never comes to this, I'll take the lower price if we just get BTC more popular its good