The other thing to consider is what you assume from a reader in a tutorial. If you assume they have a full environment setup (or will be following another tutorial), you can put together a much more concise article.
Imagine the now-classic Rails Blog in 15 minutes screencast. For those at home -- even if you assume a unix-y environment -- you might have tutorial setup that looks like this:
* Install homebrew/update package manager
* Install ruby-build
* Install rbenv
* Install ruby-2.3
* Install git
* Create a git repository
* Install bundler
* Create a Gemfile that includes rails
* bundle install
* Install rails
* Install postgres via homebrew
* Setup postgres database
* Install javascript runtime (nodejs or ruby-racer)
* finally run `rails s` to see the blank hello world page
Sometimes there are a lot of steps involved in a full end-to-end guide. And sometimes we forget all the baked in knowledge and setup we had to do for our preferred tools/stacks that we are having to go through again as part of learning a new technology.