The question is - Do people prefer Drupal over Wordpress. Is the ratio changing ?. Has the Drupal Ecosystem Changed recently ?. Lets take a look at some data points to see if we can answer these questions.
Drupal is mostly suitable to build web applications which also needs a CMS engine, Drupal is a good balance between a CMS ( out of the box ) and a framework ( letting you build things using the dev framework ). Drupal has got major UI enhancements in 7th version and few more coming in 8th version. I trust drupal for serious web application development ( not just web sites ). Also, I think drupal has one of the best open source community, some really good technical folks, and a good ecosystem around it to foster its adoption.
If you decide to take enterprize level support there are many more companies available now which provide support for Drupal then before.
Big Sites using Drupal - Whitehouse, NASA, IBM (internal), Yahoo, Adobe, Sun Microsystems, Sony, MTV, Fox, Warner Brothers, The Onion, Kernel Trap, Linux Journal, Mozilla (Spread Firefox), Wikimedia (Fund Raising), Ubuntu, Kentecky Derby.. The number keeps increasing day by day. Due to the extensibility, scalability and stability provided by Drupal.
When you want something extendable, Dynamic functionality, wordpress is not so good and it can easily break. Drupal is the best solution here, it has modules like the CCK and Views, which provide a lot of flexibility without coding skills. If you are looking for a site that has any sort of advanced features (custom ecommerce, specific site functions, lots of sortable data, advanced search or query features, etc) then Drupal is your best bet for CMS.
Drupal does have a longer learning curve compared to wordpress. But once you know its cakewalk and you will be on cloud 9 with the amount of customizations and functionality changes you can do easily.
Wordpress on the other hand is kept light and lean intentionally to cater ease of use and as a blogware. Most people using wordpress need not be very tech savy. Wordpress is by far the best when it comes to blogging website and it can even provide simple cms functionality, in case you choose to extend it. When you want ease of access, easy updates, easy management, SEO, Speed. Wordpress does get attacked much more then drupal. I have many sites running in drupal but it hardly gets hacked. Wordpress sites are more prone to attacks in my opinion, so you must ensure you install security related plugins. WordPress powers about 9% of the websites on the Internet, while Drupal powers about 2%.
WordPress looks better on the outside (administration UI) and Drupal looks better on the inside (architecture, API design).
WordPress is better than Drupal at blogging, but Drupal excels when you have more sophisticated needs. WordPress beat Drupal when it comes to usability, especially for non technical clients which is one of the main reasons why WP is winning converts
However if you don't want to deal with installing, upgrading or scaling your Drupal 7 site, take a look at http://drupalgardens.com
-- it is free, and allows you to build a Drupal 7 site similar like you would on WordPress.com or SquareSpace. It is designed to take additional complexity out of Drupal. I think Drupal Gardens could be a game changer for Drupal as it eliminates many barriers to adoption for Drupal. If you previously discarded Drupal because it was too hard to use,then checkout Drupalgardens.com So coming back to original question , I think more people are using Drupal then WordPress. The reasons are
- More support, developers available for Drupal including enterprize support.
- Many Hi-Profile companies and websites use drupal. Checkout the showcase on drupal.org
- Lot of websites offering Drupal training videos for free, thereby reducing the learning curve and getting quickly started with Drupal.