That's not a hard drive. That's a system built on top of hard drives.
And so is perkeep.
And so is perkeep.
A RAID is not magically more reliable than a single drive, it needs a bunch of infrastructure and it needs to be duplicated to some other location far away enough to ensure that a single catastrophe such as a fire does not destroy your entire raid.
You are missing the wood for the trees: hard drives and raid devices are storage mechanisms that fall far short of the boundary conditions set to keep something permanently, at worst you will store your data for a couple of hour like that and in ideal conditions maybe for a couple of years, but on a scale of decades or centuries they are useless as a complete solution, though they could be part of such a solution.
You could be made to feel better if the alert only came when it concerned your data. But even then, and going by the NAS sitting under my desk you could be months without any activity and then suddenly two drives fail in two weeks. It's a nice little random data generator.
e: Also, is it so surprising that your drives failed around the same time? It’s likely they were purchased together!