Supply and demand rule the pricing of commandos, but there's a seat for every ass as the expression goes. Some people want to build their own bike from a basket case. Some people want a CNW gem. Some just want a reliable runner. There's a lot of width in the price considerations there.
I bought my commando for $500. in '78 from a friend who couldn't fix it. I easily spent over $5,000. in parts since then. Some of those parts are consumables like tires. Some were upgraded parts. Some were modifications. The labor time for all this work is beyond calculation, and means no one would ever pay me what I've put into it with the labor calculation added in.
Granted, I've done a lot of stuff to my commando that cost good money that might not show up in higher resale value and some that might. The adapted cast wheels, the Givi frame and hard bags, the fairing, dual breathers, Jim's headsteady, kegler clamps, all should add some extra value, but probably not equal to their costs. I have a decent amount of extra parts too. I have both roadster and interstate tanks and side covers. I have a new extra roadster seat, the original spoke rims which can be swapped back to the bike to make it more original...
My bike runs great. I am not a norton builder of any note. If I asked $10,000. which seems a fair ballpark, I doubt I would get much interest at that price. At $6,500. I think it would sell easily, so the market value is probably fluctuating between those 2 numbers for your average, complete, well sorted, commando. Like most of you, I'd like the value to be greater, but I'm not looking to sell it either...