Never say never.
There have, of course, been a number of racers who have recovered from extensive injuries and gone on to race again.
Many (many, many) years ago, a friend of mine blew out a knee when he hit a gate. He returned to skiing in two weeks...on one ski. He skied the rest of the season that way.
I know people who ski totally blind, visually impaired, one foot amputated, post-polio, diabetic, etc. I have a number of friends who ski bumps at advanced ages (over 70).
There are reasons to give up skiing, but not as many as most people might think.
Most ski schools probably have instructors who ski with injuries or physical disabilities of various kinds. One good friend achieved his L3 after his below-knee amputation. Another underwent a 2-year-plus recovery period to ski on a high-tech grow-in (as opposed to glue-in) hip replacement. Today, he skis far better than I ever will.
I have broken a number of bones. I was back on skis 4.5 weeks after breaking my clavicle (collarbone). I went to the ortho (a skier himself) for the 7 week follow-up. He said, "It looks like it's throwing down some material and will heal successfully. I'll release you for skiing, but you have to be careful not to fall on that side." I told him I'd been skiing for two weeks already, and he just grinned and said, "Well, I guess you didn't fall on that side."
I broke my back in late July, 2001. I watched the World Trade Center towers fall while wearing an expensive upper body orthotic. I was skiing by Christmas (carefully, again), somewhat to the dismay of my PT.
I have been a Type 1 diabetic for over 30 years.
Learn to ski well and in balance. It's easier on your joints and reduces the probability of re-injuring yourself. When you're balanced, your quads don't scream halfway down a bump run. When you're balanced, your knees won't hurt as much. Maybe they won't hurt at all. Your back won't hurt as much, and maybe it won't hurt at all.
Accurate dynamic balance will allow you to ski longer every day, and it will allow you to continue skiing difficult terrain as you grow older. It will help you ski more easily and in less pain, despite the problems your body has or may develop.
So, build on what you can do, listen to what your body tells you, and balance well for effectiveness in your skiing and to reduce pain.
Never say never.