Show me a place that lets you to easily reset your username. Almost all social media, gambling platforms, video game platforms, games and forums don't let you to change your username because there is no need of that, especially on forums.
Just imagine how terrible it would be if everyone had the ability to change their usernames the way they wish? This will lose the track of users, I might forget who I replied to or who is this guy with new username. It will be a total mess to my mind, I'm even against the current username change that happens on this forum.