It seems fairly obvious that an airline reservation system needs to be connected to a network at least, I haven't heard many people claim they should have been

It seems fairly obvious that an airline reservation system needs to be connected to a network at least, I haven't heard many people claim they should have been all offline. But for example I heard stories of lathe machines in workshops that were disabled by this. You gotta wonder whether they really needed to be online. (I'm sure there are reasons, but they are reasons that should be weighed against the risks.) Beyond that there are plenty of even more ridiculous examples of things that are now connected to the internet, like refrigerators, kettles, garage doors etc. (I don't know if many, or any, of these things were affected by the CrowdStrike incident, but if not, it's only a matter of time until the next one.) As for the claim that non-connected systems are "very, very annoying", my experience as a user is that all security is "very, very annoying". 2FA, mandatory password changing, locked down devices, malware scanners, link sanitisers - some of it is necessary, some of it is bullshit (and I'm not qualified to tell the difference), but all of it is friction.