Anything could happen really.The situation is like Schrodinger's cat. But I would say chances are more likely that it grows bigger since I see a lot of potential and that huge companies and websites are using bitcoins as a payment method. Bitcoin is the future. I don't see bitcoin being ''dead'' any time soon. That phase will be over.
Yes, it functions well as a payment gateway and a mode of transaction rather than just behave like it as something people would invest their money in. Making bitcoin a currency as an investment, is how it serves to be the best at both the categories. I just feel the more trade takes place, the further it grows as a currency and as well as an investment as both co-depend on each other for acceptance.