Power is accounted for in my calculations. Technically today's gpu compute does wonders for power consumption. And likely to only improve from here.

In the many years I've used cloud I've never requested support, so in my experience I don't need to calculate that in.

And even when you consider machine costs, as long as you can get at least 1 yr (not an unreasonable assumption) out of your equipment you're more than making up for what it would've cost in the cloud.