Well, all of my data exists in 3 copies. One in my house, one in the detached "granny unit", and one in the offsite location that I described.

My single offsite drive is indeed a ticking time bomb, but it's easily replaceable with no loss of data when it dies.

The problematic case is when all the drives hosting the 3 copies happen to die at the same time. Perhaps I don't have good protection about this case, but I think I've reached diminished returns in terms of backups.