Last week, the W3C decided they were not going to use WordPress for their next website. Accessibility was the driving force for the final choice between three contending CMS’s (WordPress, Craft, and Statamic), but they did a lot of research before.
It mentions requirements for CMS choice, accessibility, open source vs. commercial software, performance, and much more.
Arguably, the same can be said of commercial software, it’s just less obvious since they don’t work in the open.
Commercial software rewards developers for building software which they can invest back in the software, whereas open-source software has to rely on commercial sponsors or the efforts of the community.