Many motor homes as of late do not include a spare tire, especially the Sprinter. Some RV manufactures offer one as an option, others don't even offer a place to mount one. The reason concerns the extra weight of the tire, most prominent on rigs that are already close to GVWR. Mounting a spare tire on or near the rear bumper amplifies the weight problem, over-loading the rear axle and the 4 rear tires.
To people without a spare tire, I advise to carry a tire repair kit with compressor, the kind where you use the sticky rope to plug the hole. Clean punctures like from a nail can be repaired with the tire on the vehicle. Walmart sells compact tire repair kits. The tire-on-vehicle repair is not advised to be a permanent repair, but for a clean puncture, it should be enough to get you rolling to the next tire shop for a proper repair.
Others will chime in to say that the spare is deleted to increase profits which is also true, but the primary reason involves "weight" placed in a bad place.
If you tow another vehicle, then carrying a spare is less of a crises when it happens by taking the flat tire in the other vehicle to get it repaired. Another thing a few people do is carry the RV spare in the tow vehicle.
Both our motor home and tow vehicle have a spare tire. I like the peace of mind to have them and also the appropriate jacks and tire irons.