Is a point-to-point Internet just wishful thinking? If we all just get some good antennas [1], we could point our antennas at each other multiple times a day and exchange large quantities of data asynchronously (within a small geographic area). My old TV antenna used to rotate internally when you changed the channel to locate the signal, it's just servos spinning antennas. I think there's value in both network designs. Reading articles like these gives me a hunch that fiber will never be secure, ever again, so an Internet that doesn't run on fiber is one I look forward to.
A fiber is point-to-point unless there's an add/drop along the way. A submarine cable is point-to-point between say California and Japan or New York and Southampton.
That 5GHz radio has short reach and low capacity. It'd only make sense in certain situations. It would not be suitable for the gigantic capacity required by the Internet backbones.
For example, with the advent of coherent optical technology, you typical submarine cable is carrying 4000x the capacity of that radio (4Tb/s). Terrestrial long haul systems can be easily 8Tb/s.
To what purpose? As long as it is interest from a government/powerful institution to spy on something they will for sure develop a way to do so. Nothing is safe...
[1] anything on the order of 1Gbps, 10-100km: http://www.ubnt.com/airfiber/airfiber5/