Well, isn't that what happened? At 207,000 feet, the air is still pretty thin. The combination of speed and air density make frictional heating approach maximum load at those altitudes, but aerodynamic buffeting is not as bad as at lower altitudes, where thickening air makes mechanical shock a concern. My guess is that airframe heating combined with kinetic forces (deceleration) caused the initial large-scale breakup (although smaller sections or pieces could have peeled off earlier), with some contribution by whatever aerodynamic stresses were present at that point.