I'm arguing against the hidden premise that "having a dozen different client thingies" is a potentially good thing for users. It nearly never is, and the fact that a dozen devs derived pleasure from creating them doesn't change that.

I'll go even further and claim that "user choice" is code for, "warning: nobody in this space is competent enough in UI/UX to derive pleasure from working on it." In fact in mastodon's design, it's not even code-- the "choice" of servers by topic is literally a limitation imposed on the user before even signing up. So the very first part of the UX has a circular dependency-- choose a server to try out the service and discover which server most suits your interests. It'd be like Google redesigning search so that you have to type subreddit-style topic into the URL before searching.

Additionally, this "choice" meme seems to conveniently disappear for software that has a thoughtful UI. I don't see anyone talking about the downside of Krita not having multiple other half-baked UI's than very impressive one it ships with.