Will any amount of consistent spinal decompression result in the "rebuilding" of a herniated/degenerated L5 disc?

No not in my opinion. I have not reviewed any control peer reviewed evidenve that the above ispossible it is still a working theory traction has been used since egyptian times with similar results for centuries no medical evidence for such a claim.
No. The disc has no capacity to regenerate itself or reverse degenerative changes that have occurred. Check out spine-health.Com.