The tire industry refers to tires in this condition as "run flat" which refers to a tire that has lost air, whether it is from a slow loss or an immediate loss, and then subsequently run on. As the tire continues to operate or "run" with significant amount of air loss, it reaches the "runflat" stage, where serious internal damage is caused by the excessive deflection of the casing. If the air loss continues, the inside of the deflected sidewall can actually rub against itself. When the internal abrasion weakens the casing sufficiently a blowout can occur. Additional damage is often done by the relatively sharp rim flange cutting into the fully deflated casing as it is driven after the blowout, even in the short distance it takes to drive the vehicle to the side of the road.
We are not indicating that the tire was not maintained, but simply that it lost air. Some of the many factors which can cause a tire to lose its inflated air pressure are penetrations, cuts, snags, impact breaks, valve stem leaks, incorrect mounting, just to name a few. While it may not be possible to pinpoint the cause of initial air loss, we know the outcome is underinflation damage.