There are lots of ways to explain the explosion of public cloud computing and the comparatively conservative growth of private cloud. We can talk about elasticity, shadow IT, and a number of other contributing factors.

But every once in a while, someone manages to sum up an argument in just one tweet, as Owen Rogers, a senior analyst with 451 Research, did this week. In fewer than 140 characters, Rogers said everything you need to know about why public cloud is the future of enterprise computing.

You had one job

Rogers, working on a cloud economics research paper for 451 Research, didn’t have complicated needs. He just wanted to get a price for some Microsoft technology in its private cloud. Exasperated by the result, Rogers summed up everything that the public cloud is intended to mean, and everything wrong with private cloud, in just one tweet:

Rogers’ rant was inspired by a simple request: “to know is how much Microsoft System Center and Windows Server costs for 25 servers, each with two cores, 10VMs.”

Rogers’ mood wasn’t improved by Microsoft stiff-arming Mac users who might want to dabble in Microsoft’s private cloud pricing:

By the time Rogers finally got to his “best guess” at Microsoft’s private cloud pricing, it ended up looking like a not-so-user-friendly calculation:

All of this simply confirmed 451 Research’s survey data, which finds that “71% of respondents rated the non-IT roadblocks as their biggest barriers to cloud adoption [including] resistance to change, relative to the cost models, people, time, the organization budget, and regulation and compliance.”

Or, in Rogers’ words,

Not that this is exclusively a Microsoft problem.

Private cloud, public failure

Microsoft Azure’s public cloud pricing and deployment is simple and straightforward. It is, after all, true cloud. As Amazon Web Services (AWS) chief Andy Jassy proclaimed years ago, private cloud essentially amounts to a clumsily dressed up data center:

“If you look deep into what [private cloud vendors] are offering, you will see that it’s basically an internal data center that is virtualized and has some management tools. Organizations that have private cloud systems will have missed out on all the advantages and benefits of going into the cloud.”

As I wrote recently, this is why 95% of private cloud deployments fail, by Gartner’s estimation. Private cloud, by its very nature, locks an enterprise into a certain scale and a certain way of solving its business problems.

AWS data science chief Matt Wood put it this way:

“Those that go out and buy expensive infrastructure find that the problem scope and domain shift really quickly. By the time they get around to answering the original question, the business has moved on. You need an environment that is flexible and allows you to quickly respond to changing big data requirements. Your resource mix is continually evolving — if you buy infrastructure it’s almost immediately irrelevant to your business because it’s frozen in time. It’s solving a problem you may not have or care about any more.”

Wood is speaking of cloud’s impact on big data projects, but it applies equally to other IT projects. Small wonder, then, that public cloud VMs have grown 20x in the past few years, according to Gartner’s Thomas Bittman, while private cloud VMs have managed a more miserly 3x growth.

It turns out that most of the cool new workloads that will transform businesses is happening on the public cloud:

“There are certainly examples of new cloud-friendly instances in private clouds, and examples of traditional workloads migrated to public cloud IaaS, but those aren’t the norm. New stuff tends to go to the public cloud, while doing old stuff in new ways tends to go to private clouds.”

And new stuff is simply growing faster.

This is a long way of saying what Rogers managed to convey in just 140 characters. Public cloud delivers dramatic improvements in convenience and will continue to deliver dramatic returns to those that embrace it.