Although it isn’t correct, commonly, most of us in casual play will simply realize that a drop on the cart path, once it’s executed properly, will result in the ability to take another drop from that cart path. Rather than go through all the machinations, we will generally just take final relief as if we were taking it originally from the path and move along…
This statement from the OP's post...."The earliest bunkers were natural: un-raked, unpredictable, full of footprints and debris and divots. They were genuine hazards; if you went in one, you couldn’t be sure what would happen next."
I would not have an issue if they were like I would envision the earliest bunkers. The problem I would have with then not being maintained today is, at least in the beginning of unmaintaned, you have bunkers where you get sand so deep that you can plug a ball and maybe never find it. I envision those earliest bunkers to be harder, more dirt like as opposed to this loose white stuff many prefer to see today. A little layer of sand/loose dirt would be ok. But, bunkers where you can walk in them and leave 2 or 3 inch deep footprints...no thanks...those would need to be maintained.
Since you are asking... probably now... especially if you bought that driver new.
If you plan to keep your new driver for a number of years, do it right, research new and recent drivers, hit a lot of them, and get fit. 10 years from now the difference is negligible.