I had a microdiscectomy to remove a bit of my L5 disc and I'd like to note that to imply someone can return to normal activities within three weeks is disingenuous.
The sciatic pain was relieved by the surgery, but I could only sit for a few minutes at a time a day after surgery. I had great physical therapy (personalised because my Mum is a physio) and was a model patient who always did my exercise.
I went back to work eight weeks after the operation, but could only work part time because I could only sit for limited periods of time. It took months to build up my sitting tolerance. I am now physically very fit and healthy, but you shouldn't imply that you can go back to normal activities after three weeks (in fact, it took years before I could work normal office hours without discomfort).
The rehab takes much longer, and not everyone has access to the amount of physical therapy that I had. It was excellent to avoid nerve damage (which would have caused much longer-term physical issues) but post-op rehab is an important part of healing and takes much longer than three weeks.