I saw it, you can have RAID with just 2 hard drives.Of course competent person would have a RAID in the first place so problems with one drive would not result in such trouble.
Ever see RAID in an ordinary network-connected workstation? I haven't.
While I personally run RAID for everything but my SSD most workstations don't.
In any case I don't believe in their 7 crashes theory at all.
Of course you can. That doesn't mean it's normally done. The usual procedure is workstation drives are considered expendable.