I personally don't think browsers need to be able to do stuff like exposing USB, Bluetooth and MIDI to websites. They aren't a substitute for a real OS as an app platform, and they should stop trying to become one. They're for reading (hyper)text, writing text (including filling forms), and watching videos.

An aside: as someone who comes from Android app development and now makes a hobby project that includes a web interface, making the browser do what I want it to feels like I'm building a UI in a Word document, complete with macros. The ability to have this free-flowing text that isn't contained in anything, this whole concept of "inline elements" still hurts my head. I'm too used to real UI frameworks where any text is only allowed to exist inside a TextView.