IE - customers you don't really want to be stuck with in the first place.
Drupal is fairly big here in Scandinavia, and it's my distinct impression that it's the same story all over Europe. It has a strong footing within online media that seems to grow every day.
I suspect that if I moved to another country, or even abroad, I wouldn't have much difficulty finding a different (high paying) job related to Drupal.
Also, if you're US based and like great community oriented dev houses: www.acquia.com, www.lullabot.com or www.palantir.net.
http://www.acquia.com/customers
Just one subset, of course. Doesn't include customers of other major vendors.
Of course, they also want superb design and UX so things usually end up going over budget as we have to hack the hell out of Drupal to match the level of UX desired. Every single Drupal project I've worked on I've wished I could be using a real framework and code from scratch instead.
Unfortunately I don't see the perception of digital agency project managers changing much. They still think they can get the best of both worlds.
My Drupal knowledge is well out of date, but the indisputable fact that the Drupal architecture like all software architecture imposes assumptions, many many more assumptions than a low-level framework like Rails (which tries to keep its assumptions as broadly applicable to all HTTP usage as possible). These assumptions imply tradeoffs. If you think there are no tradeoffs you need to step back and realize that Drupal has corrupted your mind and the limits of your web development ability will be constrained by whatever ideas Drupal core is able to harvest and integrate from the wider world of web development.
In my experience, Drupal is ideal for cheap clients who want a zillion features but don't have the budget. You can deliver more functionality in Drupal than anything else, that is absolutely true.
For high-end clients who are willing to pay for impeccable UX and solid problem-solving, I can rarely recommend Drupal because it starts with a raft of assumptions that tend to lead to subtle compromises in the UX but would require an inordinate amount of effort to fix.
I ditched Drupal for Rails specifically because I hate being in the position where I have to explain why a seemingly simple change would require far more work than logically makes sense (to be fair, this is an occupational hazard of programming, but with Drupal it happens to an obscene degree). Going to Rails felt like targetting a higher class of client.
Meanwhile Rails developers seem like some of the most sought after programmers today. Where is this elite Drupal employment world that the OA speaks of?