1. If you’re depending on a single local drive to safely house your data you don’t have to lose an encryption key to lose your data.
2. Apple and Microsoft both provide user-friendly cloud-based recovery options for FileVault and Bitlocker that leverage iCloud and Microsoft accounts, respectively.
2.5. “But what if you don’t want to trust/use cloud services?” See #1. You can’t depend on your single drive anyway. If you can be responsible for safeguarding backups you can be responsible for safeguarding encryption/recovery keys.
3. Organizations and probably most individuals rely on professionally managed storage solutions to house important data. Organizations don’t tell their employees to store important things on their local laptop, it’s Box/Dropbox/Drive/etc.
4. Considering how most computer users are on laptops, removing the drive is not a practical suggestion, even if the laptop has an easily removable drive. That type of knowledge and ability is beyond the vast majority of computer users.
That’s why, to me, the best way to operate is on a full disk encrypted device that’s treated as disposable. At any time it could be stolen, fall on the ground, stop working due to a power surge, get wet, etc. If your workflow involves device replacement causing lost data you’re already in a vulnerable position.