"One possibility is that we have a shortage of programmers. If that’s the case, you’d expect more programmers to enter the field, bringing down compensation."

"One possibility is that we have a shortage of programmers. If that’s the case, you’d expect more programmers to enter the field, bringing down compensation." This is true. I was a mechanical engineer professionally. I moved into software engineering, and the increase in compensation was a dominant factor. I know several other non-CS engineers that have made the same move. While it's not driving down compensation per-say, the difference in demand between disciplines is startling.