[_puk]

How does that make economical sense?

I can pay to render everything for my user, essentially streaming their webpage to them. Or for the potential cost of a slightly slower page load I can offset the cost of all that rendering to their xGHz multi core CPU that's likely sitting idle.

Not to mention the cacheability of the data.

[jjnoakes]

Because bloating your client's experience has negative effects too: lower battery life, lower performance, higher memory usage, ...

[z3t4]

It would make digital rights management (DRM) easier. Companies already spend a lot of money on DRM. There are already services today that lets you use a remote desktop for computer-aided design (CAD) work or gaming. But as you said, it's not economical yet.