@grey @r000t Run flat tires are kind of garbage - a lot of damage to tires is the kind of damage run-flat tires can't handle - so when a tire gets damaged in a way a sealant kit can't repair (and a run-flat tire can't handle), you really need a spare tire, but you don't have one (and you can enjoy paying Mr towman).

The extra material needed for run-flat tires furthermore increases the weight of the tires and therefore you only get a minor weight saving over a full sized spare.

The real reason is how the company can get (negligibly) more profit if they don't include an extra tire (since 4 tires with extra material costs a fraction less.).