An interesting episode and I can understand why QF is not your favourite carrier right now.
On the specific matter of 'flexibility', I think it's difficult for any airline when asked to bend the rules. There will, in fairness, be countless cases such as your own (ie people
just failing to maintain their status level), and for the most part it makes commercial sense for the rule to be applied uniformly so that everyone knows where they stand from the start.
The harsh reality is that there is no airline, or other travel supplier, that can be guaranteed to meet all your expectations throughout the entirety of a relationship. There is no shortage of evidence here on FT that loyalty is fickle on both sides ; the best you can hope for is that whichever airline you choose to spend your money with will keep you happy most of the time.
Safe travels