It is more complex than it used to be, but too complex? Our tools have finally matured to solve some of the worst problems with Ruby development (ie. monkey patching, namespace conflicts, forking to fix bugs, gem development, etc). It's definitely worth the effort.
You did an excellent job on your guide, but a lot of it looks more complex than it actually is. This guide is more than just Rails, you also walk through installing RVM & Ruby. Setting up a Ruby environment from scratch is somewhat complex. But once you understand RVM, getting started with Rails 3.1 is actually quite easy (but it's always a little more complex in the .beta and .rc releases).
Installing the current, stable version of Rails hasn't ever been too complex, but trying to stay on the bleeding edge can be a bit tricky.
Using rvm certainly helps, since it can keep your gem environments separate, that too involves a bit of initial setup.
Edit: Okay, now I see you're also the author of the helpful doc. And I do agree with your comment as well. I think adding extra steps (like using RVM) do add extra time and complexity to getting a proper dev setup running, but I think it's worth it in the long run.
The difference now is that there are clear steps to follow for success! It may seem like more steps but before you could spend hours futzing about with gem versions, then discovering that your current apps no longer ran, etc.
