Logical and economical storage of image archive

Not quite.  There was a noteworthy white paper a couple years back about the failure of raid to deliver its promise.  A key argument made is that recovering from a failure is when other weaknesses in the backup get exposed.  This was a particularly bad aspect of RAID 5 recovery - while one drive showed obvious failure, the massive reads/writes around a recovery exposed bad blocks on another, ones that weren't obvious before.

So if you backup to old hardware, you need to do more than just verify you can log into it or read a few files off of it.