There are many older and more venerable file transfer protocols, like FTP or TFTP. Add encryption and then you have SCP and SFTP. SFTP is the default protocol used by the scp command, and TFTP is still often used to communicate with routers and access points and similar equipment.
And I'm not sure what that has anything to do with TCP not as reliable. TCP has real problems on the modern Internet but the first part does not imply the second part.
That's not a problem with TCP, that's more of a problem with IP itself. Connections are currently identified by the source/destination IP and port numbers, but that should not have been the case. Imagine we use a UUID for the connection and keep an updatable cache between UUID and IP.
Still nothing to do with TCP.
Also, this kind of partial file transfer protocol is still needed because what if a host crashes? Even if we completely solve the mobile IP problem we would still rely on both ends of the connection tracking state. That state is lost due to a crash or power failure.
And I'm not sure what that has anything to do with TCP not as reliable. TCP has real problems on the modern Internet but the first part does not imply the second part.