Rev, I strongly disagree with your last statements.

A communication protocol similar to MIDI is nowadays as handy as it used to be.

So is a file standard similar to the MIDI file format - a different topic, but related. Such a format is by no means a poor-man's substitute for MP3 etc., but has its own semantics and reasons of existence, in very peaceful coexistence.

What has gone is the need for utmost economy in terms of bandwidth and file size, that came with a trade-off considered too high nowadays. New standards are highly desirable and easily designed; the problem being of marketing. But even if a new standard were agreed upon, MIDI would still be supported "forever".

A format uniting the features of notation with most of MIDI is MusicXML, fortunately well-established now - after long struggles with software vendors. This gives us hope for a MIDI successor as well.