That explosive decompression would automaticaly lead to in flight break-up.
This is more exception than rule
It wasn't just a simple decompression. There was also a big blast wave from the missile detonation, as well as shrapnel from it.
There were perforations which a "normal" decompression would not have. So it would open up along those like tearing toilet paper along perforations. There is that one piece often photographed, which was just behind the cockpit, curled back before it tore off. It would loosen the next piece it is attached to, before totally separating. That gives the next piece a protruding edge (and distorted profile) to start peeling back from.
The cockpit came down more or less in one piece because it has a triple strengthened frame and skin (to resist bird strikes and hail). And the main fuselage damage started behind the cockpit, so the floor and right side still held it on, while the business class port wall and roof ripped off in one joined piece. The starboard wall came off later, and the floor twisted and broke next. With the plane "scooping" wind, port wing control surfaces damaged and port engine not running, it would have to be falling in a sharply banked dive, probably the first half of a spin dive. that would be enough Gs to separate the floor and drop the cockpit.
The sudden change of centre of gravity, coupled with more "scooping" would have levelled it off a bit and certainly turned it to port about 80 degrees. Possibly adding a last "flick" to the tail that would be the last straw/Gforce to break up the rear into 2 sections. It all broke roughly along the lines where the sections are joined together, as these are the weakest spots. Wing tips fell off, either shaken loose or being hit by other pieces of debris.
With 1 1/2 wings and one dead engine, the heaviest strongest wing section then continued on to crash at a flat low angle, probably no faster than a fast landing speed (it didn't go in deep and it didn't leave a skid furrow).
Oh and another thing -- in decompressions where the plane remained intact and flyable, there always were PILOTS left to fly it and controls left to take their commands. Here the pilots and the avionics were the first to go.