Market economy. In the US there is a perception of shortage and so wages are artificially increased (as compared to other industries of equivalent skills/experience/challenge) to account for that perception.
The reason that perception exists is a misalignment between how developers are produced, the skills required by industry, and the things employers are willing to do to compensate for that supposed gap.
It's an opinion so I am not sure what you are hoping for. If you are actually interested in the subject, as in doing more than trolling, perhaps you could find citations of your own and post them here.
The reason that perception exists is a misalignment between how developers are produced, the skills required by industry, and the things employers are willing to do to compensate for that supposed gap.