OK, my experience is far less than yours and a lot of other people here. I have two Volvos and both of them had had the ignition switches replaced by previous owners, and I had to replace one of these as well. And since I had to have access to the ignition wire to install my Crane Cams electronic ignition system, and I know a lot of Volvos have them installed, I assumed that there are a lot of old Volvos without the armored cable.
Personally, I don't think the armored cable is very good theft protection. If a thief is prepared he can cut into it fairly easily.
But, if you like to keep things original, I can understand wanting to keep the cable. But it sure gets in the way when you have a problem with the ignition switch or want to replace that old coil with one with a bajillion volts.
Tom