Electricity is sold by the kilowatt-hour. Now a researcher has proposed that computing power be sold by the computon
If a 500MW power station could only be built by putting fifty thousand small 10kW generators in racks, with expensive complicated machinery to try to keep as many as possible fueled and running at once, then I don't think the concept of an electricity grid would ever have caught on. But that's what a "computing" power station looks like.
There are some slight economies of scale to computer hardware, mainly in management overhead, but compared to the cost of putting your own computer at the other end of a wide area network, they're negligible.
The amazing thing is that this idea keeps cropping up, year after year, despite the fact that the basic technology just does not exist. Maybe it will one day, although currently it's moving in the other direction.