I have read the various comments against the OSI model and the one interesting observation is that none of you seem to have ever worked with a compliant implementation of the OSI model. Honeywell had a commercial product called DSA (Distributed Systems Architecture). We did write distributed applications that used the OSI protocol stack communications and it worked well. Within the applications, we didn't have to worry much about what was happening at the lower levels as those levels simply provided specific services we used. It was used for many years with very good results.

One of the features of the software at the time was that you get two dumb terminals to communicate with each other across the network by simply using the relevant connection protocols. This allowed simple communication streams to occur without having any applications involved, it was handled by the protocols themselves. It also meant that it was very easy to replace those dub terminals with an application without having to change any of the configurations in the network.

TCP/IP rose to the fore due to various reasons that were not related to their technological superiority. To see this you have to look more closely to the history of those times.