Back in the day I made loads of custom switch boxes and so on to allow whatever bizarre system I thought was a good idea into a reality - in fact I only got the last one out of my studio about 3 weeks ago when I finally removed the 19" rack I've had in there for the last 20+ years. The ubiquity and compatibility of MIDI has been one of the reasons that it's still around today. Forgetting that would be a huge mistake, IMO.
If you wanted to switch to something common, I'd personally say Ethernet (or something "normal", and a specified transport over Ethernet). Handles the distances and data rates more than fine, parts to implement it are widely available, it's already used more and more in stage and recording setups, so specialized components are available too. In the audio sector, standards to distribute precise clocks are around, one could maybe reuse those to get it past P2P connections (although that kind of gear is still kind of expensive right now). Still quite a step up in complexity though...
MIDI is the lingua franca of music equipment. It controls mixing consoles and effects units, it synchronises music to lighting, it provides timecode and controls recorders. You might not use that stuff, but it's an essential part of the spec that is used every day by professional musicians and engineers.
I think they're saying one should use rugged USB cables for live performance, rather than a typical consumer-grade cable.
If MIDI2 can work with USB-C in a way that devices can be linked, instantly, because the USB-C circuitry they use can speak just enough USB to verify the connection is between two MIDI devices, then I will be more than happy to give my MIDI cables away and never bother with them again.
And yeah of course a stage or studio setup will still need them for the foreseeable future, it's not like decades of midi instruments vanish overnight. But you'll also start seeing USB cables thrown into the mix, and eventually you might not see MIDI cables at all in 20, 30 years.
It has to start somewhere.
USB wasn't designed for this use case, and it is a very, very common problem.
Certainly, UBS in general can't be used for this purpose, but if there's true industry buy-in for MIDI over USB then it's not hard to imagine more and more USB hardware will get made that can compensate for that problem. For instance, I wouldn't imagine laptops to get isolated USB, but a shiny new post-MIDI-2 audio interface sure would.
In that environment, isolation is a constant concern. Connections that are inherently isolated make fault-finding far more straightforward and obviate the need for external isolation boxes.
For even a simple USB audio interface setup connected to a single audio source I would recommend isolation and balanced audio cables.
There are a lot of potential technologies that could improve upon the antiquated MIDI cable standard, but USB is actually worse in a lot of ways.
CAN bus might be a good option; it's fast enough, and is already available on a lot of cheap microcontrollers. I haven't worked with it, though; maybe there's a shortcoming I'm not aware of.
Then there’s the fact that many manufactures promise MPE support in their devices, but rarely in 1.0 firmwares... you either ship with it or wait 6 months for either a crummy implementation or a statement from the manufacturer walking back support. It sounds like a non-trivial software implementation task, especially on devices with resource starved I/O processors