No one knows for sure (with any degree of certainty). Having said that, most agree the future is bright. That statement does have a few caveats. The following is my prediction:

Bitcoin itself as a protocol will evolve. Many people forget the simple fact that it is a protocol first and the money part just happens to be the first app written over it. Think of it like the Netscape browser written for (predominantly) HTTP. It was good at its time, but then other browsers took the mantle and Netscape was dethroned. The same analogy could apply to bitcoins (the money). It could be dethroned and for all we know Dogecoin or Litecoin could prevail.

The Buying process of Bitcoins will have to be made much more simpler than it is at present. All indications point that the process will get more streamlined, so buying bitcoins will be an easy task.
In most countries (US included), companies that trade Bitcoins onto the local currency would be regulated. More exchange companies will mushroom.

Until and unless Buyers keep pressing / asking Merchant to accept Bitcoins, merchants will be oblivious to the demand. If you walk into a store and ask if they accept Bitcoins and they answer No, this is the expected answer. Repeat this scenario with 10 other Buyers asking the same and the Merchant will think differently. They just might start looking at Bitcoin acceptance.