So I take it "El Reg" is not backed up either?
It is absolutely trivial to wipe out data in any RAID or SAN/NAS. Simply tell it to consider an empty or foreign drive as part of a set/volume, and it does the destroying for you. Force load a corrupt or empty configuration. Plug in a drive that spits out "impossible" responses that were never programmed against. Seen it done manually, automatically, even done it myself.
It is also customary to store data in effectively non-recoverable scattered and compressed format (e.g., Microsoft Outlook PST, although that was done for vendor lock-in).
Company-saving backups are NOT the responsibility of a T&M vendor. Data copied to a different area of the same <whatever>, while useful, is absolutely in no way a backup. The only valid reason I can think of not to have several tested backups is that Ballmer had them destroyed as favor for one of his T-Mobile-competitor friends.
Seriously, whatever data you have at Google, Amazon's cloud, Microsoft, etc, is probably NOT backed up, merely replicated. This can protect against certain hardware and network failures, but your data is always just one programming error or one tired technician away from complete destruction.
None of the above companies would fail to backup their own company-critical data, but neither T-Mobile nor their business nor their customers nor their lawsuits are any more critical to Microsoft than your Hotmail spam folder.