Li-Fi is one attempt https://en.wikipedia.org/wiki/Li-Fi

Most of it is, yeah? Fiber-optic cables transmit via laser beams.

Actually p2p file transfer via an infrared port[1] was a fairly common feature on laptops back in the day (this was probably before bluetooth took off). If you're on Windows, have a look in the "Network and Internet" section of the Control Panel. You may still have an Infrared utility there if your computer has that functionality.

[1] https://msdn.microsoft.com/en-us/library/aa940293(v=winembed...

Data transfer over QR codes http://stephendnicholas.com/posts/quicker-video-qr-codes

You can probably use a phone's flash and camera for bidirectional data communication with another phone some distance away.