So here I go again.
I've written at length on this blog over the years about Drupal. It's a great tool for getting things done right now. It's seen a huge uptake over the last couple years among government agencies and educational institutions, so being versed in Drupal development is a good career bet at the moment, meaning over the next couple years.
In the longer term though, I see it as pretty shaky and here's why.
Drupal's raison d'etre is that non-technical users (meaning - people who aren't programmers) can build fairly complex sites without writing a lick of code. It has seen massive growth, mainly because the fact that websites are actually computer applications with which users interact is a fact that is really just dawning on the majority of people who use the internet and/or need a website for their business. Most people don't have CS degrees, but every business needs a website. Thus, they either turn to someone who knows how to build websites, or they hook up with GoDaddy and do a one-click install of Wordpress.
I think the world at large is rapidly getting used to the idea of writing code, and the proportion of people out there who are at least somewhat comfortable enough with that idea to hack together their idea is growing. And their idea might not be a good candidate for a Drupal site. The other thing about Drupal is that whatever your idea is, you can probably get pretty close without writing code, but chances are high that it's not going to be exactly what you want without writing some code (or hiring someone to write some code). And at that point, you either settle for something that isn't what you want or you teach yourself to write some code. And after you get comfortable with writing code, you start to wonder why you are dealing with all of this Drupal overhead that you didn't ask for in the first place. And some time after that you might find a language like Ruby, that makes infinite more sense to me than PHP, and looks a hell of a lot prettier to boot. And soon after that you might find it hard to get excited about Drupal work, because overriding other people's code is way less fun than writing your own to begin with, and that's the vast majority of working with Drupal code, at least form the backend.