I've built plenty of very real Django apps without any of these (except ssh). Heroku's not the only platofrm, Ubuntu's not the only OS. Neither are even significantly mainstream in the industry.
This tutorial is so myopic. It reads more like a recipe from a beginner's cookbook than anything else.
I've also built plenty of Django projects without a lot of the mentioned utilities, but that doesn't make them any less useful or recommended. I'm certain the developer knows that Ubuntu isn't the only OS and Heroku isn't the only deployment platform. I'd argue against the mainstream statement. Ubuntu is one of the more popular server distros used. Do you expect someone to cover every possible platform and PaaS provider?
What Kenneth is offering is obviously a guide with recommendations and not requiring you to use them for your projects. It's ultimately up to the developer to decide what to use.
I became a much better developer after I tried to port my Django apps to dotCloud and Heroku, using these PaaS forced me to really learn how to use git, virtualenv and pip.
Chef and vagrant are going a long way towards giving me most of the things I love about Heroku and dotCloud but with more control.
This tutorial is so myopic. It reads more like a recipe from a beginner's cookbook than anything else.