Evolution is slow process its not sudden change and there are various factors which affects the its development from one to stage to another so we don have to be much concerned about the same.
And I believe good craft man with his polished skill set won't get lost in future. If he is good at what he do and he do that perfectly then no one can take his place.
A perfect example will be senior VFX supervisors at ILM, they all started with opticals and now they doing the same job in digital environment. They got adapted easily. It all depends upon your passion and your know how in the craft.Compositors have to do what he is assign to do I don think their will be change in work a compositor in future. May be, he or she may face more challenges and difficulties but on the other end the technology is making things simpler and easier.
Production pipeline is all about specialization! A pipeline is there in production because jobs must be breakdown to people who are good at doing particular job. And finally one man can't do every job from pre production to post production.
There is no need to feel insecurity for compositors because this field is getting more exciting day by day. But we must be ready to learn new stuffs and broaden our know how, these days I feel a sound knowledge in 3d is a must because more and more compositing softwares are supporting real 3D environment and objects inside the composition.
I think, in future Compositors will be doing more work which have assigned to lighting, texturing and rendering artist now! So who’s is going to suffer at the end? Compositors or 3D people?
Well there is will be need of specialized person now and in future until technology makes things child’s play! And finally as long as there is some art in our job we all will be unique just because everybody's style and execution differs…