We’re talking about wavelengths here as an aside, because the topic can distract from the core issue of how wireless data is transmitted. The wavelengths used for public wireless have been standardized to the 2.4GHz and 5GHz bands; think of these as the “cables” used to transmit the data.
The 2.4GHz wavelength has been key, because it’s an all-important wavelength that, in most of the world, is an open unlicensed frequency. Why is that important? The 802.11a standard was adopted in the United States, and was based on a 5GHz wavelength. Able to transmit twice the amount of data as 2.4GHz, there were strong moves to have 5GHz the de facto wavelength at the end of 1999.
The problem at the time was that outside of the States and Japan, the 5GHz range usually required a license; in some regions, it was restricted for military use. Both factors delayed release and greatly increased the cost. This changed in 2003, when the frequency was freed up in Europe, due to the increasing demands being put on the 2.4GHz range, but by then, it was too late for 802.11a, because far cheaper and easier-to-implement 802.11b and g gear had swamped the market. Another troublesome aspect is that the 5GHz frequency is more readily absorbed by walls, cutting the working distance dramatically, and negating most of the speed advantages. The truth is, with radio waves, it’s not their speed that matters, it’s what you do with them that counts. But for 5GHz, its advantages would come back around….