I want to know what people actually believe to be the backup strategy used by their host.

This is an interesting area because although 99.99% of hosts say that they back up your data....their AUP (Acceptable Use Policy) always claims no responsibility for your data.

What do you consider to be a real backup?

It's all about costs.

A tape backup solution costs money. Not only for the drive and media itself but also for the space (usually you need a bigger case which costs monthly in the noc) and for someone rotating tapes.
If more customers would ask for such a feature and are willing to pay a higher price more hosts would implement tape backup. Same applies for off site backups