You missed the point of the OP's post - the company sells a backup service, which means losing a customer's data is a very bad thing. Breaking open retail external drives and moving those hard-drives into a server is not something that inspires confidence in their ability to actually keep the data safe.

The OP's point was a confidence issue, and not necessarily that there was a better option that could have been taken.

The pods have internal redundancy, and your data is stored on more than one pod, so I'm okay with them using consumer hardware to back my data up. They also wouldn't be doing it if they weren't sure that the drives were reliable enough for that use.

That's one of my favorite uses of probability: if you know what you are doing, you can build extremely reliable systems out of unreliable components.

Even the best hard drives will fail eventually, so you need a redundant failure-recovery system anyway. And once you have that, using commodity hard drives shouldn't be a problem.