Agreed, there is no such thing as perfect software.

In physical world, you can specify a tolerance of 0.0005 in but the part is going to cost $25k a piece. It is trivially easy to specify tolerance, very hard to engineer a whole system that doesn't blow the cost and impossible to fund.

Great software architectures are the ones that operate cheaply, but are bulletproof when software fails. https://en.wikipedia.org/wiki/Chaos_engineering