I liked the metaphor however the author (s) failed to mention the cost associated with Cloud and related services: the more a variable cost your usage is the greater the per usage cost, holding all else constant.
Extending the metaphor, if you only want pizza once a month, yes it may make sense to order in (SaaS in their analogy). However if you want it every day, ordering in gets prohibitively expensive and you may only have limited choices.
So if you eat pizza 5 times a week, buy the ingredients, buy lots of different ingredients so that you can have exactly what you want (turkey? happy thanksgiving everyone) and make your own pizza (colo, managed services etc => private cloud) and order in the sushi you only want once a month (public Cloud) – a hybrid solution.
At Canada151 Data Centers we are simply the store that provides many of the ingredients and we work with purveyors of all stripes to provide the solutions you need.