Bitcoin will certainly be the main coin in the future because nowadays the world has a lot of people use it for commercialization.
To answer short it is, and not just bitcoin, many others will have nice future too. I am saying that all the time, its not question anymore will it be, will it happen, I'm sure it will question is just when will it happen and are we patient to wait that to happen. After 3 years I am sure in that, I think people who are here longer then I am thinks the same, you need to understand where bitcoin market was years ago where it is now, some can doubt in bitcoin future, but in my opinion this train can't be stopped anymore. Machine is working with full power, new markets are arising, new countries joining, big companies finally decided to get into blockchain, to short the talk all things we have talk about years ago are happening, price is high too, and this is only a beginning. Many more good things waits us, and all that will come, use your brain to understand all this and you will see it too.