I have owned my Norton from new in 1976 old new stock 74 Commando, have never had any problem getting parts, been getting my parts from BJ's here in Brisbane since 1978 always has everything I need, but lucky my Norton hasn't need to many parts more upgrades to me and of course since the internet things are easier to source worldwide and so many upgrades now that were not even thought of back in the 70/80s, most of my upgrades are sourced overseas now and only use BJs for things I need in a hurry and lucky that is rare and it's been sometime since I had parts sent from OS, not since the last major build/upgrade about 12 years ago, for some reason my Norton just keeps going and is very reliable in the way I have built it and keeping on top of the maintenance plays a big part in that, was a everyday rider till 2013 and is now semi-retired, it's been retired from everyday riding.
But it's great we still able to source our parts and great upgrades that wasn't around in the early days of ownership, my Norton is showing it's age but it has some great upgrades and is always a one kick starter even when it sat for a bit.
Ashley