@evan
Some of those messaging systems taught us nothing. They came and went, leaving no trace. But, ASN.1, an X.400 component, lives on in every mobile phone on the planet, in cryptographic certificates, etc. ASN.1 inspired Googles' protobufs and now CBOR. Even JSON looks like ASN.1's textual representation.
Don't be too quick to dismiss the value of the battles we fought back in the 80's.