The number of backups a person has depends on the amount of money he has to take backups and the importance of the data. Drive prices are through the roof every year in India. I doubt anyone keeps more than 1 backup of their data. Banks and other organisations with unlimited money would go the 3-2-1/2 way. Normal people probably zero or one disk.
The 3-2-1 backup is for important data, like documents and maybe photos. Photos don't really need more than 2 copies (1+1). For most people it's maybe a few GB at most. 3-2-1 is not for pr0n and dvd-rips !