The M x N interoperability problem is SOLVED BY building on top of bytes /
    plain text, not solved by moving AWAY from it!

I never argued that we should move away from plain text. Indeed, one of the examples I cited of an interoperability format, JSON, does exactly that: it takes plain text and adds structure to it to make it easily parseable by machines. Overall, I'm not sure what part of my post you're arguing against. I'm suggesting that instead of having a many different ad-hoc formats, Unix utilities should agree on a few accepted serialization formats and pass information around using those. This would make our shell pipelines less complex and more robust because we wouldn't have to worry about e.g. random spaces or newlines breaking the ad-hoc parsers we write with `grep` and `cut`.

It seems like you agree with that, with the caveat that that serialization format should be built on top of plain text. That's fine. We can agree on JSON as a serialization format. It's not ideal, but it's better than the myriad of ad-hoc formats that we have now.