The format doesn't adequately reveal to the layman what's what here. The fundamental is about 9dB below that 2nd harmonic, and the laymen won't know that's about an 1:8 power density differential. Nor will he know that if you add the total power density of the 2nd, 3rd and 4th harmonics that they will run closer to 15dB higher in content than the fundamental. In short, the insignificance of the fundamental in this case is far less than it appears to those uninitiated in how to read the chart. But it's a start in the right direction. Partly because of the string length, partly because the sound sample I assume was measured with a mic, and not a pickup that's mounted well back on the string. You'd see a goodly difference between bridge and neck pickups too.