Don't forget that the Lightning network is going to be rolled out this year :-D That means transactions as cheap as 1 satoshi each that will confirm almost instantly.
Eventually Bitcoin will have to move to some sort of POW/POS hybrid in order to be profitable in the future IMO. We could also see a dramatic shift in users over to another blockchain such as ETH or LTC. Bitcoin is the king for now- but for how long?
There are already alternatives that exist as we speak that are faster and cheaper than Bitcoin even with the lightning network
Steem being one.
Bitcoin was the true innovator, but like with MySpace it will be overtaken with new and better technology.