Not to mention the hours wasted by users.
The cost to the company may well escalate, but there's not much mention of the number of hours wasted by users trying to get some buggy software to work properly, How many reboots. Multiply that by the number of users and your talking about a huge waste of time to everybody because one programmer couldn't be bothered to check the return codes on functions. Yes, that's my pet hate, programmers that don't check return codes. Yes it takes longer as you now need to think about dealing with failures but if you want solid reliable code always check return codes.