One issue I have seen in distributed systems is where a library is on another customer/teams hosts and brings them down due to a bug in the library. The other customer/team has no way to fix the bug and is dependent on getting the attention of the company/team who vended the lib in the first place. One I remember is where a library had a bug which created 0 byte files and exhausted the inodes causing an outage.
Cloud systems have become cheap enough and flexible enough that protecting your customers by not putting your bugs on their hosts is not as big as a lift as it used to be when you had buy bare metal servers or explicit VMs.
The first hysterical blindness was documented by Herodotus in the battle of Marathon, "Epizelos the son of Cuphagoras, while fighting in the close combat and proving himself a good man, was deprived of the sight of his eyes, neither having received a blow in any part of his body nor having been hit with a missile, and for the rest of his life from this time he continued to be blind"
The US would have been able to replace their aircraft carrier losses pretty quickly, far quicker than the Japanese. By the end of the war the US had close to thirty carriers IIRC.
Engineers always under estimate the amount of business logic in an existing application. This is one reason my mainframe apps are so hard to replace, they often have 30 years of business logic built into them.
There is the (internet) story of an engineer that could only log in when he was sitting down. Standing up he could not login.
The problem was he had cleaned his keyboard a couple of days earlier and put some keys back wrong. When he was sitting down he logged in by touch typing. Standing up he looked at his keyboard when he typed.
When the teams I worked with switched to kanban, they liked that they didn't have the end of scrum deadline, they also disliked that they didn't have the ten day deadline anymore as they felt the arbitrary deadline helped to push them a little.
That being said, kanban is better, it is more relaxed and feature feedback is faster than scrum.
Yeh there is an account updater service you can integrate with. So if you change cards it will expose that through the service and a company's billing service can continue unperturbed even if you change cards and credit card numbers.
Cloud systems have become cheap enough and flexible enough that protecting your customers by not putting your bugs on their hosts is not as big as a lift as it used to be when you had buy bare metal servers or explicit VMs.