There are too many Commandos for them to be a "valuable collectable" so they don't fit into that market, unlike, say, a Vincent Black Shadow. So that means that the market is, as has been noted, for somebody who's REALLY intro retro (as in a real vintage bike as opposed to a retro-styled modern bike) and the required maintenance. Also as noted, that market is becoming smaller and smaller as we age.
I have a 25 year old niece that is into bikes - has a KLR - and likes learning to do her own maintenance but she is the only young person I know with such an interest. None of her friends share that interest and her 27 year old sister absolutely could not be bothered using any product, technology or otherwise, designed or created anytime before "last week!"
I think the Commando market will continue to reduce in size. Sure, a pristine, unmodified, like new example will probably always bring a decent price from a collector because even though there were a lot of Commandos, there are very few low mileage unmollested ones which is what always brings the most money.
I'm always amused by the fascination for "original" examples for anything other than collections - vehicles that will sit in a garage or wherever and not be operated. Because back in the day, an unmodified moto or especially a muscle car just didn't exist on the road for very long after purchase. I don't know of any owners back in the day that didn't immediately slap headers, an AL intake manifold and a different carburetor(s) on them. So a "normal" muscle car was a modified one! I drove a 440 Road runner from the dealer to my house (37 miles) and immediately disassembled the engine to install higher compression pistons, and the aforementioned headers/manifold/carbs.
"there’s an argument to suggest that as life becomes more digital and dull and homogenised, folk might just look to things like these quaint old fossil fuel burning antiquities."
Not sure I agree about fossil fuel burners but vinyl - what we used to call "records" - seems to be doing quite well. Local sounds shop has 4 turntables in the front window! Go figure...