I've had many HDD failures where not the mechanics failed, but the electronics making up the communications interface. Because of their small size many electronics components are very sensitive to even minor electrical irregularities (this can happen when large A/C motors nearby are turned on/off etc. and the power supply is a little on the cheap side).
When the drive's internal power converters or capacitors (energy storage buffers) burn out the electrical signals generated at the HDD's external connectors can and will move way out of specification. Since the drive is connected to the controller via copper wires, and often in servers many drives share a cable connection to ease installation and reduce clutter, this can easily disrupt or even permanently destroy any number of adjacent components.
This has very little to do with pricing by the way. It is true that expensive controllers and drives MAY use parts that are more tolerant to abnormal conditions or have better shielding, and that with budget components you are more likely to get sub-standard parts. But I have regularly found identical capacitors on a $50 drive and a $500 drive. And if a failed HDD directly routes 12 Volts from the power supply to the SATA connector because something shorted out, your RAID controller will be fried, no matter how many figures the price tag had.
It's not what usually happens, but it's definitely not unheard of in my experience.