I hate the "what if" game. It is hard to think about the unknown.
As with everything, you will deal with whatever happens. I am sure that twenty years ago, if you had any idea that your arm/leg were going to stop working, you would have played the "what if" game and wonder how you are coping with what MS has done so far.
"What if" I had never had MS and never visited this forum? I would have had less character because I would not have known you and learned about you.