Or just get another drive and backup to that - that's the beauty of backups, if one goes down, you have a backup - or am I missing something?
I got the impression that 'backup drive' actually meant 'external drive' as it isn't backing up anything.
Otherwise, I agree with you (although if it's just corrupted files rather than hardware damage just re-format and start again).
I learnt my lesson many years ago when I accidentally (don't ask) formatted my drive and installed an OS. Was unable to recover hardly anything from the drive and lost lots of photos. Now I keep 3 backups of my photos. One inside the machine, one on a NAS in the garage, and one off site (at work). Better safe than sorry.