This is spot on.
But, I disagree with your last statement:
> Day After sites will be rendered on the server again; because we are now working with extremely "complex" 3D hologramed Apps.
Data is data is data. When the problem of distributing, syncing and querying data distributed between client and server is solved, it is solved forever for all classes of application which are built on that paradigm.
This is true whether you're rendering a 2D web page or a 3D holographic image from that data on the client. There would never be a need to go back to server management of data or state - that's why leaps forward in this space, which React is and now Relay looks like it will be, are incredibly exciting and pull the whole industry forward.
I would suggest a more likely 'Day After' problem would be managing more granular distribution of data and state through networks of clients, i.e. apps built on the peer-to-peer IoT paradigm rather than today's dominant client-server paradigm.