Do you think there will ever be a version where we can really say bitcoin consensus rules are set in stone forever?
In other words, is a version planned thats never ever going to change except for bugs/UI and to keep the base up-to-date for OS/lib/toolchain changes.
Yes I think that is possible, if you add privacy and security updates to the list of "allowed changes". The most important rules of the Bitcoin network are already effectively set in stone - coin release and maximum number of coins possible. Given the current scaling debate, people might get the wrong impression that there is widespread willingness to change every single rule, Bitcoin is operating on. But in fact, most efforts center around making Bitcoin scale efficiently.
So I think it's possible that we may see a "final version" of Bitcoin in future. The reason is that Bitcoin itself can remain a relatively basic system - experimentation and new innovations can happen in 2nd layers and sidechains. Bitcoin will just be a framework for more complex structures built on it.
ya.ya.yo!