In defence, software failures aren't measured in lost revenue. They're measured in operational risk. A 2016 GAO report revealed that the US nuclear command-and-control system coordinating ICBMs still ran on 1970s IBM Series/1 hardware using 8-inch floppy disks, with replacement parts so obsolete they had to be sourced from museums and eBay.1 The system wasn't fully decommissioned until 2019. Meanwhile, nation-state adversaries are actively exploiting software supply chains: the SolarWinds breach showed just how deep that vulnerability runs.
Battlefield communications, intelligence platforms, logistics systems. They all run on code that's harder to maintain every year and a bigger target every day.
1 GAO Report GAO-16-468, 2016