It's still a thing because Darksiding makes good sense for those of us that do a lot of highway miles. I'd LOVE to do it, but I have no space for tire changing equipment, no nearby buddies with tire changing equipment, and all the tire stores refuse to put a CT on a motorbike.
I'm sure someone will mount a car tire on your
side car wheel if you take it in off the bike. Aside from the first attempt, I never had to do it myself or use a friend.
Most indi HD shops will do it, or Wing oriented shops. Places that sell trikes, etc.