Other 747's sat on runways in Saudi Arabia, hotter tarmac, for longer times, and didn't blow up when taking off.
Prior accidents involved poor maintenance, one was a bomb placed by men dressed as 'maint crew' , on foreign soil.
Tests were unable to get the CWT to explode.
They had to run much higher current than the wires were designed to handle (meaning the current was never that high in the actual 747 CWT's) to get it to 'pop'.
(hook a small diameter wire up to both posts of your car battery. Same results)
Why were those airframes not grounded? Before or after?
Why do TWA and Boeing mechanics and pilots argue against the findings of the FBI (NTSB was herded by FBI)?
The big question is why the FBI was making the findings at all. Once the NTSB ceded their natural jurisdiction of the crash investigation over to the FBI, the final report's conclusion was assured.