Wordpress is similar to forum software in that the modern landscape have diversified and depending on what you are trying to accomplish there are a ton of alternatives. Almost none of them are a reimplementation of what Wordpress does though since it comes from a time where you would purchase shared hosting that came with Apache, PHP and MySQL built in. It’s a giant monolith that is as widespread as it is because 90% of everyone who started a website in the 2000s used Wordpress.