My concern with WordPress is that we may end up with something akin to the free-rider problem mentioned in the article. Whereby the code is maintained by a small group of people – or in WordPress case – a small group of companies (Automattic, Google, etc) and most of the freelancers are either hired by those companies, or stop using the project because it’s going in a direction they don’t like.
We’re already seeing this to a degree with Gutenberg. People who were once diehard WordPress developers are now broadening their horizons. Many still use WordPress, but they may also consider alternatives now, where they used to use it by default.