I agree about not expecting any backtracking on “legacy” ports. MagSafe was pretty innovative when introduced, I wouldn’t rule out Apple innovating on connectors again but I would expect it to still involve the USB Type-C interface.
Don’t hold your breath, but I don’t know that the Touch Bar will stay forever. It doesn’t seem that successful, it’s a “Pro only” feature (i.e. not included on the MacBook Air), and they haven’t introduced an external keyboard with the feature. In 2016, when they embiggened the TrackPads on the MacBook Pros (same year they introduced the Touch Bar), there was some speculation that Apple was laying the groundwork for it to become a touchscreen (at least I speculated). If that actually happens, I think there’s a good chance the Touch Bar would go away.