As previously mentioned Bitcoin's usage is not very wide spread. We have estimations from banking writers like Jeffrey Robinson who claim there is only as little as 250,000 people using Bitcoin. To put into perspective, to again reference something Robinson had said, there is more people with club membership at Air Arabia Airlines than people holding Bitcoin in this world. Even on the higher side of estimations, being 2 million Bitcoiners, there were more people using the internet in the late 1980s than this higher estimation. It was a regular lie last year when all the hypers and pump and dumpers were claiming this was like the internet in the 1990s (not even remotely close)
Since the numbers are so low it's quite certain, unless Bitcoin beats some other coin to the punch, that somebody will come along and figure out how to achieve exponential user adoption and it won't take 6 years to surpass Bitcoin - you can get more than 250,000 people in mere weeks to use something if it goes viral and it is considered cool.
You are absolutely right, but it won´t be an altcoin with a killer feature.
It will be an APP/DAPP on a platform like NXT or Ethereum, and in the beginning the users won´t even know what they are using.
