There's always a chance, even the creator awares about that, so we will see the answer in the next 6 years. 
Right. Otherwise we couldn't have a finite limit of 21 million coins, because there would always need to be some minimum reward for generating. In a few decades when the reward gets too small, the transaction fee will become the main compensation for nodes. I'm sure that in 20 years there will either be very large transaction volume or no volume.
With that statement from the creator himself just assures that anything can possibly happen. But looking on the situation, we'd definitely not going to see it any time soon that it will be gone.
Maybe in the nearest future, the interest might just be stable and not that be much anymore because of how things could change like having not that much fluctuation anymore.
Remember we're currently on he situation where the governments are trying to adopt Bitcoin, moreover most people don't aware with decentralization, this will make centralized exchanges, institutions and governments hold almost Bitcoins that already circulated.Maybe in the nearest future, the interest might just be stable and not that be much anymore because of how things could change like having not that much fluctuation anymore.