source: https://forum.cryptonote.org/viewtopic.php?f=2&t=192
You can pretty much forget about anything significant being added to BTC, unless there is a major change of leaders and philosophy. BTC in the year 2100 will look about the same as BTC of 2014. Maybe the side chains thing will go in, but even that seems questionable.
This is normal, and probably healthy. Technological progress often happens by leapfrogging, not evolution. The idea that "we can just merge the features" don't work once something because mature and (often well-founded) conservatism sets in.
bitcoin may evolve and innovate more features in the future and will very well be the no1 crypto for quite some time.
BUT bitcoin wont adopt any anon-technology, at least not decentalized in the qt-wallet. bitcoins main goal at the moment is to seek law compliance and to become truly legal in important economies. no way they will adopt anon-tech and shoot themselves in the foot.
bitcoin will stay anon-tech free for quite some time and another (illegal) crypto will emerge and fill that gap. maybe drk, who knows.