If you have been monitoring the statistics, like I do, you can see that most CMS, like Drupal, Joomla, and Typo3, and Magento, have been slowly bleeding market share. This is a part of a wider trend, where the smaller brochure sites are being overtaken by the drag and drop builders like Wix and Squarespace. However, if we take this fact into consideration, then we still need to explain why WordPress has been growing in market share all along. I will ignore the other CMS at this point. Here is the explanation, why Drupal has been bleeding market share, while WordPress has been gaining.
Putting the general picture described above aside, there is another reason why Drupal went into decline after version 8 was released. Drupal 8 has been rewritten to be more industry-standard in its structure and code. While it made Drupal 8 vastly superior to Drupal 7 and WordPress code-wise, it also became much harder to learn and use for amateur developers.
Amatuer developers consitute a whole layer of a CMS ecosystem. Though it is customary for high-grade developers to look down on amateurs, they play a number of vital roles in the ecosystem.
- First, they service the lower segment of the market. Brochure sites, budget work, small and inexpensive tasks and fixes.
- Second, amateur segment allows an easy entry, an "industry lift", where a developer with a minimal entry level can start earning and growing.
- Third, it provides a marketing ecosystem for businesses that make and sell themes and modules that the lower market segment actively consumes.
- And, finally, it keeps a CMS' hold on a market share, keeps the CMS "popular", does not let it fade into oblivion.
A huge part of Drupal's loss of market share comes from the loss of this low-end market. Drupal until version 7 included was guided by the wider community. At that point, however, the higher echelon of developers decided to change its direction for the upcoming version. It was decided that the dollars behind the development would also decide the direction for the CMS. This was the fulcrum, changing everything. Larger companies got to push their decisions for Drupal's future, that no longer cared for the smaller companies and amateur developers, who now lost their voice. This destroyed the lower-segment Drupal market and forced the smaller Drupal shops to either merge for weight, or drop Drupal support altogether. This is how Drupal lost it's "underbelly", resulting in a swift drop of the market share.
I believe that the actual reason Drupal has lost it's 2x market share since it's peak with Drupal 7 has been the loss of it's underbelly. The system was rebuilt to be a technological marvel and attuned to the needs of high-end businesses (this is what is usually meant when Drupal 8 is said to have become "enterprise"). The lower-end market, however, has suddenly found Drupal to have an even higher learning curve, higher cost of development and support. Technological marvel or not, you can't use it if what your client wants is a small site with a purchased template to offset the cost.
It's true, that over the last few years Drupal 8 "caught up" some - it's modules infrastructure is again abundant, it has some themes available for use, and the distros like Thunder, Open Social, and Droopler (my favorite of the three) will give you a very low start in website building. The downward curve has been stabilizing. I expect it to level out once Drupal is settled within its market niche. The lower end market though does not seem to be recoverable at the moment.