Traffic is not the only way to make money in domains - regardless of what some long-time domainers believe.
You can buy income stocks and you can buy stocks that grow in value. Some domains appreciate in their reseller value, which is an anticipation of end-user demand plus pure collector interest. (The collector value of domains is a little discussed topic, and I wonder how stable it is. Nevertheless it is a significant factor.)
So, prime example, many people are buying 4 letter .coms in anticipation that they will soon be unavailable to register. The thinking goes that at that time the perceived value will rise. This is the normal cycle in a growing market, as the LLL.com, LLL.net, CCC.com, LLL.org, LLL.info and LLL.us markets have demonstrated in the last few years, to the great profit of those who were invested in them at the right time.
There is an end-user market for LLLL.coms, perhaps thinner than I would like it to be, but they do have the advantage of being very short and simple for law offices, for example.
There is air in the domain market - a cause for concern. In all areas there are many parked domains sporting extreme price tags hoping for the end-user who must have that one domain. Some of those domains do sell. It is a very curious business.