Greetings smart bovine.
"how was it that 'its not flying' was not made obvious?" As a computer person you will appreciate the number of if/thens required to provide a definitive 'it is not flying' to cope with all possible events and failures.
Each false or failed input that enables you normally to identify 'it is not flying' has to be 'protected' against generating a false warning on its own and in an 'and' scenario with other units. We have already seen the fallacy of the '2 out of three' sensors voting at Perpignan.
Then you must decide what to do about the situation. We are treading (some unwillingly) down the path of 'the machine will sort this out' so what will you programme to 'pick up the pieces, establish which values are right and then do ???????????? The other (my preferred) option is to ensure a basic skill set for aviators (until the perfect 'HAL' comes along) and 'drop' the misbehaving now basic a/c into the ?capable? hands of a pilot., who, while suffering the logic/thought processes you describe, has that un-progammable intuition/experience.
It may, of course, be that 'fuzzy logic' or whatever is around now will achieve your ideal.