Great points Cruise Zombie
I alluded to differences between countries in an earlier post. As has been said, this is often a self limiting condition as the disc dries out or dessicates. It shrivels up and no longer presses on the nerve root which is the cause of pain. My take on it is that if you have significant symptoms you have a risk of long term immobility which makes it difficult to return to work so treatment is needed. A bit of an ache for a couple of days can be left.
Injections of local anaesthetic and steroids is the most efffective way of terminating symptoms but physiotherapy which reduces the pressure on the nerve also works.
Yes your prolapse cant disappear so it is still there until the disc dessicates but can as you demonstrate be controlled