Yes they have runflats. But run flats are an urban thing. 100 miles at 50 mph seems like a lot, if you live in the city. But can be the distance to the nearest paved road in the Western US.

Besides I hope to replace the run flats at the first opportunity. I know how, and am more than willing, to change a tire if it is flat/damaged. I don't need stiff riding tires for 20k+ mi., just so I can drive with no air in them - < 100 mi..

I realize that the space saver spare has a lot of the same limitations BUT... after I ditch the run flats, I can get a tire fixed at nearly any gas station. And in a pinch, I can plug the sucker myself.

Funf Dreisig