I respected douglas so much as they actually tested their planes with thrust reversers deployed to see if you could still fly them. Boeing relied upon theoretical calculations.
Not true, Boeing did flight tests with a T/R deployed as well, including on the 767 (IIRC it was a regulatory requirement to flight test it). But they did the tests at relatively benign conditions and the engine already at idle when the T/R was deployed, not at 24k/Mach .78 and the engine at max climb (i.e. Lauda). Even though the FADEC retards the thrust to idle, it comes down the normal decel schedule which - at those conditions - takes over 10 seconds to get to idle. With a T/R deployed on an engine at power, the reverser efflux basically wipes out the lift on that wing and it drops like a rock. By the time the engine got close to idle they'd already lost control of the airplane.
BTW you are correct about the 737 - it has a tendency to 'float' enough that the squat switch WOW wouldn't go true - so they use radio altimeter.
Newer Boeings, such as the 747-8 and 787 use a combination of both radio altimeter and squat switch (I don't recall off hand what we did for the 777). At least one radio altimeter (less than 5 ft.)
and one squat switch need to indicate ground before you can deploy the reversers.
Lomapaseo - NO system is 100% reliable. The certification standard for flight critical systems is less than one catastrophic failure per billion flight hours (10-9/hr.). Since Lauda, Boeing T/R systems are among the most scrutinized systems on the airplane - and even taking into account potential latent faults, the probability of an inflight deployment is ~1 per
trillion flight hours (10-12/hr.).