Some travel without spares and belong to coach-net, Good Sam etc where the dispatched repair service SHOULD be able to fix you up with a new tire.
The problems I have with this are; The cost of the brand they will sell you versus the cost in a non emergency situation. They may not have your size tire which means you could sit for 3-4 days if a long weekend. If the service you prefer screws up or they cannot get you someone because your half way to nowhere, you have NO WAY to get going again.
I belong to Good Sam but I have all I need to change a tire should I have to. I never want to but I can if needed.
My thought goes back to when I had a Winnie Chieftain and the MH was stuck for 4 days in Scranton Pennsylvania because no one had that size tire, IIRC a 19 inch one. The nearest place according to the company I dealt with was a warehouse in South Carolina. No the price was not bad but the wait made me resolve to have a spare. I now carry 2 as I travel the South west. It has come in handy more than once