No-one uses MIDI 2.0 yet, we don’t need it! MPE (https://www.midi.org/midi-articles/midi-polyphonic-expressio...) is only just being adopted (with poly aftertouch instruments and keybeds like the ones in the ASM Hydrasynth).
MIDI has proved amazingly resilient, whether over 5-pin DIN, the increasingly common TRS 1/4” jacks (common on Eurorack or guitar pedals, where space is a premium) or the utterly ubiquitous MIDI over USB. (And ethernet, can’t forget that). Everything digitally controlled speaks MIDI - and not just music, the stage lighting world is all MIDI too. I think that there is a real case that it’s the second most successful wired physical-layer protocol behind Ethernet.
[1] - http://www.dmx-512.com/dmx-protocol/dmx-protocol-basics/
I remember the first time I saw MIDI in action: I was in a mall in the mid-to-late 1980s and ComputerLand had a full sized keyboard hooked up to an Apple IIgs, which was playing The Entertainer while the notes scrolled across the screen on a color display. The real piano sound that came out was piped through some great speakers and I thought it was the most amazing technology I had ever seen. Think about that for a second: That tech remained almost untouched for 35 years. Incredible.
1986: MIDI and the MUSICAL MICROS | BBC Archive: https://youtu.be/aADkqmvy44o
Related note: I recently found this video about making electronic dance music on an Amiga in the early 1990s and learned quite a lot about how music-techies back then we're geeking out. Super fun - I'm not a musician, so I honestly had no real idea what was possible back then.
https://youtu.be/6OaBkvwx7Hw