People keep talking about cloud as being, or needing to become, like a utility. The analogy is that users don't want to own a power station, they want to close a switch and have the light come on.

I love analogies, and I especially love following them to their logical conclusions - so that's what I'm going to do.

Let's look at an existing utility like electricity. At least in developed countries, it's true that users don't spend a lot of time worrying about the generation and transmission of electricity; they just turn on the light.
Businesses, however, can't afford to do that. The potential consequences of anything happening to disrupt the electricity supply are just too drastic, so businesses mitigate that risk with batteries and generators. Serious businesses test their equipment regularly to make sure their IT can keep operating for a while and shutdown gracefully if the electricity supply is ever interrupted.

    The fact you have a contract for electricity to be delivered over the grid doesn't mean you don't need UPS and gensets on site, and Schneider Electric, Rolls-Royce, and many others are doing very well selling that sort of kit despite the fact that the electricity grid has been a reliable reality for decades now.

The same applies to cloud: even if you have a public cloud that is as reliable as the electricity grid - a high bar indeed! - you will still need some amount of private cloud for the services that absolutely cannot go down or be disrupted in any way.