'Trying to look at things in a different way'='our product is sub par'
To be picky, it's true that 'spin speed and disk cache were no longer the key-overriding factors in the storage industry' however access time and transfer speed *are*, and they're closely related to spin speed and cache size.
Power consumption has been reducing regardless of supposed 'green' credentials, and many drives have the ability to restrict speed and thus consumption at the expense of performance.
Even if a system has 10 drives in it, greater efficiencies would be gained by energy efficient CPUs, better power supplies and the use of fewer expansion cards, plus of course that bane of power consumption : graphics cards, if it's anything other than a server with an embedded 2D only chipset.