Doctors operate everyday on people because of spinal arthritis (stenosis). Often, they do a fusion. However, since I see the results of this everday in my job, I declined surgery about 5 years ago and just live with it. A great decision. However, if you get significant nerve impingement (hits the sciatic nerve, causing that unbearable pain into hip and leg), sometimes surgery is the only hope. I got lucky and the herniation backed off the nerve after about 12 weeks of pain I couldn't live with forever. Back still hurts bad once in a while. I can't carry loads as long as I used to; can't play with kids as long as I used to; cant stand or walk as long as I used to; but I can still do everything I used to, within reason and for shorter periods of time. Occassionally, I'll get a numb or twitching calf muscle, but nothing like what it was.
You are correct, that there is no real "cure" for stenosis. If you smoke, quit. That alone will often make a difference in the blood flow to the lumbar disks. Exercises and OTC pain meds are really about all you can do (most prescription pain meds just make me (more) stupid and itch). Getting older certainly sucks, but it beats the alternative!
Our bodies do have a great ability to heal themselves to a point.