So there are two things in vscode, which make it interesting solution for remote development.
One thing is that it is based on Electron. This has enabled Microsoft to create Visual Studio Online[1], which is vscode accessed through browser (backed by container/vm hosted at Microsoft)
Another thing is the architecture which splits the IDE into client and server. It's not about file system access via SSH. It's actually the core of the IDE running on a remote machine and the UI part (client) talking to it via ssh connection.
Would be interesting to know if this was actually the master plan for vscode right from the beginning or if they realized these opportunities on the go.
[1] https://visualstudio.microsoft.com/services/visual-studio-on...