In your specific talk, you didnt give much specifics until you said----
macbooktj
saying the volume can't be repaired after 3 attempts.
Obviously 100% accurate online diagnosis is not foolproof, however at that point yes, conclusion would be impending mechanical failure of your drive.
Most above mention "reinstalling.....", but thats the cart (OS) before the (dying) horse (your HD) đ
I assume most of them are assuming you KNOW your HD is on its last leg and you need a new HD .......then "installing....."
The ideal way before the OS got/is (?) corrupted would be to have a HD clone...... the pros keep clones of their HD,..... so when mechanical failure occurs, you yank the bad HD, and toss in the new,....and be 100% up and running in mins. .........nothing to install, or recover etc. etc.
good to have a TM backup for fresh data backup, but the HD CLONE makes quick recovery a dream, ....removes the stress, the reinstalling ....etc.
The talk about "backups" is mostly dirrected as you protecting your valuable data BEFORE the HD finally crashes and burns.
By "OS failing" your consideration is the files on the HD are 'fine', but are failing as meant the HD is corrupt and dying, so same thing, a distinction without a difference,.
like trying to get memories out of someone with a head injury, obviously. đ