The value could easily reach $1 million considering how little supply there is available on exchanges. The more people hodl their coins for the long term, the less availability of supply there is. I'm not saying it will for sure reach that price, but it could.
Currently we're dealing with so many entities trying to get themselves up and running here, that we'll face a point at which the leading exchanges won't have hundreds of thousands of coins in their cold wallets anymore, but closer to a tenth of that figure. If you also take into consideration that these Bitcoins aren't just meant to be traded on the USD market but also on the altcoin market, you'll realize how little the supply actually is.
Imagine a time where governments and pension funds will finally get their feet wet, they'll usurp so much of the supply that the price could easily swing to $1 million per coin.
Why would they need to acquire more coins and make it go to 1 million if they can buy more satoshis at 10 thousand per Bitcoin? Look at it my way. You have Bitcoins at current price and want to introduce a million new investors to the market. Each of them will need to have some coins to be able to buy things. They could buy a million coins each driving the price much higher or they could buy 10% of the coins and use satoshis to trade. 1 Bitcoin at 1 million USD will be able to serve as a means of exchange to thousands of people. How many times in your life were you able to spend more than 10000 USD at once? Most people don't need to hold that much money and most people don't have large savings they only need to exchange coins every day but they don't hold them.