I'm not sure that the OSI people even realized that they were in competition with anything else. I think they basically neglected the low end of the market.

At the time there were multiple LAN protocols that were mostly used for file sharing, Netware, Appletalk, NetBEUI, etc. You had NFS for TCP/IP but it wasn't really used for anything other than UNIX workstations.

Probably it would have required somebody to write a cut-down OSI stack for MS-DOS that could be linked to a particular killer application (whatever that was, maybe FTAM).

This would still have had to compete with the way that TCP/IP was able to swallow up the other LAN protocols, we wouldn't have had to go through the IPv4 to IPv6 migration though.