In some cases, driving on worn tires is the cause. Often the tire gets a slow leak and people either don't have TPMS due to the age of the car, or they ignore it because it comes on whenever it gets chilly out. They drive as the tire slowly drops in pressure until the heat buildup causes a blowout.
I had it happen on my last car, which did not have TPMS. A rear tire developed a slow leak and finally blew at 80 mph while passing a large truck. Because it was a rear tire, I never felt the car start to pull or wander. The only thing I could do was put my foot down to straighten out the sudden weave, pass the truck and pull over. By the time I did, the tire was shredded.
When I was in the South (shudder) I noticed a lot of unsafe cars on the road. I live in one of the few states that still does safety inspections (like MOT) for vehicle registrations; unfortunately, we are doing away with our program for 2018. Now all enforcement for unsafe vehicles will be on Highway Patrol and they will have to see the problem and pull over the offending vehicle. There is no way for them to keep up.
When I lived in California, a state with no inspection, the number of unsafe vehicles was insane. Roads were coated in a thick layer of dripped fluids because of all the leaks; it is one of the reasons California drivers can't drive in the rain, there is so much shit on the road it is like driving on ice.
Another problem is that, at least around here, Highway Patrol does not enforce load laws. People drop cargo on the roads all the time. My current windshield has two large cracks and three chips in it from debris kicked up from passing cars or gravel dropped by dump trucks. I get new glass in next week, which will be the third windshield I've had in this car. Kiki's Taurus is on the second windshield.
Debris is a big problem here. A few years ago a motorcyclist was killed when he hit a queen sized mattress in the middle of the freeway one night. Ladders are pretty common, as are construction materials like plywood sheets and 2x4 timbers for framing. I've obliterated a few things with the Xterra's armor when I just had no where to go and didn't want to drop anchor in the middle of the highway to get rear-ended.
Debris is often the cause of the blowouts you see, tire debris rarely causes a flat, but will leave a nice black mark on your body work and make a hell of a thump when it hits the undercarriage. My heavy off road tires have saved me from many flats just driving to and from work.