This article seems to have confused one key item and missed another, both of which are important considerations.
Firstly, whilst a bit pedantic (and even debatable), it confuses "on premise" with "running your own kit in someone else's data centre". Yes, I guess someone else's data centre still counts as "on premise" and this will be the route that many take, but the article completely skips like, y'know, actually running stuff "on premise" and related issues... like where to put your kit if it's in your offices, how to power it and how to secure it, and so forth. Not everyone will want to run it in a data centre (for most people, most of the time, that's what Clouds are for!)
Secondly, if you start "in the cloud" and want to migrate apps "on premise", will it be even possible? It's all about the apps, and this point is completely skipped. Most smaller or startup organisations that use the cloud are using specific applications and services, not plain IaaS. Can those apps even run on-premise? You're going to have a hard time moving Salesforce, Box, Slack or AWS's development stack on-premise. This is only going to work smoothly if you're running conventional apps on IaaS in the cloud (or, arguably, move from Office 365 to a hybrid Microsoft platform).