Regulations (as sibling comment mentioned) is one aspect, but also the cost of screwing up is real-world. A status quo system that isn’t screwing up has a much

Regulations (as sibling comment mentioned) is one aspect, but also the cost of screwing up is real-world. A status quo system that isn’t screwing up has a much higher bar to replace where the risk that the replacement system will screw up. Much of the same reasoning and even more extremely applied, is medtech - hence why you see many medical imaging setups still obviously running a version of Windows XP.