No the improvements are gradual and try to clean up some of the design of Morphic but as you can imagine backward compatibility has to be retained because there is loads of Pharo tools, apps , code and libraries that rely on Morphic and Morphic's design. Even if Morphic is replaced at some point it will be a very gradual process and still some compatibility will be retained to keep things familiar for experience pharo coders.��
Most of all Morphic is by far the biggest and most complex pharo library so producing a replacement it wont be a walk in the park. So yes you can rely on the fact that things will stay not exactly the same but pretty similar for a very very long time. If I had to say an estimate I would say at least 10 years down the road.��