We've had a spare since the day we started RVing. Our first motorhome (2001 Winnebago Adventurer) came with one mounted on a wheel and stored under the rear of the coach. We had the occasion to use it a couple times when we ran over some debris in the road. It wasn't hard to change since the wheels were only torqued to 160ft. lbs.
Our new one like yours didn't come with a spare. We decided to carry an unmounted spare under the bed. Our reasoning is that even though you may be able to get a road service to respond, it's not likely they'll have an exact match to the tires on your coach. We also carry a jack, torque multiplier, and proper size socket so we can change a tire if necessary. It's a bit more difficult to change a 22.5" tire since they are torqued to 450 ft. lbs.
In the case where no road service is available the plan would be to remove the flat and take both it and the unmounted spare (in the toad) to a garage or tire store to have it mounted. Then return to the coach and mount it.
Some people don't feel comfortable doing this, and don't travel to places where road service is sketchy. We like to go to out of the way places and would rather be prepared to depend on our own resources if necessary.