blackbird69: TWA 800 and Hughes Airwest 709 remained in one piece while the cockpit was gone.
Neither TWA 800 nor Hughes Airwest 706 were at cruising altitude. TWA 800's center fuel tank exploded around 13,000 feet and Hughes Airwest 706 collided with a F-4 Phantom at about 15,000 feet. MH 17 was cruising at FL330, so the pressure differential between the cabin and outside was higher and sudden decompression would be more destructive.
Also, TWA 800 lost most of its fuselage ahead of the wing, and the rest of the aircraft progressively broke up as it descended.