I respect the fact that the tolerances are pretty tight for the angle of re-entry, but I don't see how they could be that tight.
I am betting that the official inquiry will eventually conclude that the tiles on the left wing were damaged.
IIRC, the tolerance is on the order of a half degree.
I think (do not quote me), that the margin of error is closer to 1-2 degrees. One of the early re-entries was hand-flown by a Marine pilot, just to see if it could be done. Also, right up until the loss of data, despite the rising temperatures in the left wing, Columbia was flying in the groove.
I am betting that the official inquiry will eventually conclude that the tiles on the left wing were damaged.
Next questions, if that is the answer; how/when? I can come up with essentially 3 theories on that; the foam strike, a piece of debris while in orbit, and just the wrong tiles coming off.
The foam strike is a prime suspect (it is about as clear as it can be while watching a shuttle well downrange that it did happen), though it ignores the fact that similar incidents in the past have not caused an appreciable amount of damage. What may (I stress MAY) not have occured before is pieces of that foam getting between the tiles, which MAY (again, I can't stress that enough) not have been fully-considered by NASA.
A piece of debris has a mysterious appeal, though it is actually quite possible. At orbital velocities, a strike by an object (or series of objects) too small to see from the cockpit or on any radar could have damaged the tiles enough to cause key ones to fail. Related to that, but discountable, is a cululative toll of this effect; while Columbia was on its 28th mission, it was only its second after a major overhaul.
That leaves the wrong tiles coming off on their own at the wrong time. As a percentage of tiles do come off the shuttles, both during launch and re-entry, it could have been only a matter of time before a sufficient number came off from the same general area to cause a cascading series of events, with that time having been yesterday.
My guess is that it was a combination of these factors, which could not have been predicted beforehand, that doomed the crew of Columbia.