There's also the historical issue that the ITU championed OSI, while the IETF eventually formed around IP. OSI was a plan-everything, top-down-control, internat

There's also the historical issue that the ITU championed OSI, while the IETF eventually formed around IP. OSI was a plan-everything, top-down-control, international government system, which reflects the ITU's own structure. It's hard to get involved in the ITU. Anyone can join the IETF. OSI's remnants are basically the concept of a 7-layer stack and the X.5yy standards that became certificate formats and, drastically simplified, LDAP.