This type of infrastructure is not insta win for many(most.. ?) of businesses. Even if the price will be low and the power consumption will make a difference, still there will be HUGE cost of rewriting software.

Not all businesses need to write scalable software, because their current technology stack is just good enough and will always fit to one beefy machine, but on the other hand it will never fit on one ARM server module.

ps. hardware is cheap, while engineering work isn't