I bet if all you operated on was athletic body types that are non-smokers under 50years old you would have really good outcomes.
The reality is the people that go to spinal surgery are usually overweight, with poor nutrition, and do not want to do the rehab that is necessary to have a good outcome.
Why do you think most people end up with bad disc. Rarely is it a specific occurrence that leads to a bulge or herniation. That is why when MRI's are done they generally have a degenerative component that is seen. The degenerative component takes years to develop, it did not happen overnight. Therefore even though the pain they feel was brought on by the lifting and twisting the problem was underlying for years... hence the straw that broke the camels back.
Name a surgeon that only takes people that are fit, with good nutrtion, non-smokers, and have overall good lifestyle. Therefore patient selection excuse goes BYE-BYE.
As far as the epidurals... I send people for them before they go see a surgeon. They effective rate is about 25%. Again the real world plays into the outcomes and effectiveness.