How many Norton owners are on this forum?
I would guess that well over 1000 Commandos are represented here. Of the 20 or so Commandos I've seen down here, I don't think any of their owners are on this forum. That tells me that only a fraction of Commandos are represented here.
It's just a WAG (Wild-Assed Guess) but I would bet somewhere between 10 and 20% of the original Commando production are roadworthy today, and perhaps another 5% in restorable condition.
I think the reason so many Commandos are still around is twofold:
The bike was highly regarded when it came out
The bike was the last piston-engined model Norton sold (was the Commander ever sold outside the UK?)
My '73 was a basket case when I got it, and had not run since at least 1985. If it was a Kawasaki H2 or Suzuki GT750, it would likely have been crushed long ago. But since it was a bike from a defunct company, it passed from one owner to another for 23 years before being put back together. Nobody was willing to junk it.