WordPress = car with aftermarket mods
Drupal = custom built racing car
Joomla = bicycle assembled at a scrapyard
WordPress is a blogging tool that people have contorted into a CMS. Reddit.
If you are a site builder (non-programmer) Drupal is going to be a steep curve. If you’re not familiar with Composer and command line work, you’re probably better off staying with WordPress.
Why WP is popular. The world isn’t only made up of tech startups who have web engineers on staff. WordPress main attribute is that it’s extremely accessible and available. It’s easy to set up and get going.
Why have we still not built something modern that directly competes with WordPress?
Remember most websites, and apps are built to solve business problems and not to showcase programming languages and frameworks. The winner will always be the tool that is the most efficient and convenient.