It doesn't have to be "too time consuming" to have some kind of backup/failsafe system that will enable people to muddle through for a short time whilst waiting for the network/cloud computers to be restored.
Why immediately shred any paperwork as soon as it's been scanned? Instead of typing straight into a Word document as a file note, why not write by hand on a file and scan/photograph it into the computer?
For things like lists of appointments, what's the harm in the system automatically printing a "day sheet" at close of business the day before "just in case" something bad happens overnight?
Why can't "cloud" based systems be set up to automatically do a data dump to a local PC or hard drive at close of business every day, so at least a local PC could be used the next day if the network/cloud goes down.
These are the kinds of things I've implemented in my 40 years or working as for a decade or two during that time, I was responsible for IT in the firms where I worked! It's just common sense to me to have backups in place. Back then, I was acutely aware of our network servers failing, hence backups to local PCs, but these days it would be cloud storage that is vulnerable. I also ensured that we never had "automatic" updates switched on, on any computers nor servers - when it was time to do updates, we rolled out slowly, checking every step of the way, across all the computers in the firm.
I run a small accountancy practice and have dual redundancy for all our records. When it's done efficiently, it barely takes any time. I could go into work on Monday, not turn on any computers at all, and do a full days' work, just from basic paper files that take next to no time to keep updated and relevant. Yes, it would be slower, but I'd not be letting any clients down. The main time drain would be updating the computers on Tuesday when I switched them on again, but the chances of any of it happening are very low, so I'm not bothered about it. I'm more concerned that it would be as close to "business as usual" as possible on the day of an outage, and I'd worry about catching up and updating afterwards.