If you are making a marketing website, Wordpress is great. Also, all marketers and bloggers know how to use the admin. I have seen several website projects go off the rails because some developer involved felt that they were too good for Wordpress and turned the job into a personal hobby horse with some "superior" framework that resulted in an end product unusable by anyone else.
Even better if they use their "own" superior framework, because they can do better than Wordpress :D
Well, I saw both. Wordpress and Typo3 filled with dozens of custom modules and "from scratch apps" with half baked solutions.
Maybe it just feels to me that the customized CMS-consultancies are in the majority, because they do their stuff for marketing-customers, so they have more skill in getting the word out.
Slightly irrelevant: I once was in a team where part of the solution involved one dev "hacking Drupal into oblivion" (seriously, that description is incredibly apt). In the end, he had a nervous breakdown and quit the company.
This was mostly caused by unreasonable expectations and a tremendous pressure on the poor guy, but I still like to think that trying to turn Drupal into an eldritch abomination had something to do with it...
I mean, seriously, I've seen too much devs out there, hacking Typo3, Wordpress or Drupal into oblivion to do their bidding.
There are hundreds of companies just doing this.