My kneejerk reaction coming from the '90s is that if I wanted the same branding for everything, I’d just use Apple or Gnome. At the same time, constructing brand image on top of a third-party base that is in development and can change over time can be difficult, or just “not worth the $RESOURCE”. So I’m currently in the position that something like “universal Mastodon view with brand accents” would be the most fitting thing for the Fediverse.