There's a bunch of reasons but for the most part I'd say it's currently too expensive to do (time and money). People think they want unhackable software, but t

There's a bunch of reasons but for the most part I'd say it's currently too expensive to do (time and money). People think they want unhackable software, but then they realise it will cost 1000 times more and take 100 times longer (and even then not guaranteed) so they forget about it.