Indeed. What is he talking about?
Teaching coding to high school kids in under-performing schools is great, and may help some of them find an excellent career path they might never have thought about. But I think Carson is raising false hopes in many of the kids by exaggerating the potential impact of the program in their lives.
He seems to have totally forgotten the reality of supply and demand. It may be true that right now entry-level developers can command $40,000 a year. However, whenever it becomes well known that workers in a certain field can command high salaries, it motivates many more people to enter that field in anticipation of earning those salaries themselves. This tends to cause a glut in workers, and salaries fall as the competition for jobs increases.
One sign that this is already happening is the rapid increase in enrollments to computer science undergraduate programs over the last several years.[1] Adding thousands more to the pool of available workers will only bring salaries down farther.
The more high schools this program is successful in, the more this effect will come into play, especially if the program gets "rolled out to every high school in America" as mentioned in the article.
Also, companies naturally seek to minimize costs by looking for cheaper sources of labor through outsourcing to other countries or by bringing workers from other countries here on H-1B visas. This is already happening.[2] As time goes on, these efforts will likely be increasingly successful, and will impact entry level jobs the most.
I think it would be much fairer to the students to tell them this is one skill they might be able to base a successful career on, if they have an aptitude for it and are willing to put in the effort to get really good at it. Otherwise, he's placing unrealistic expectations that might eventually hurt the students if they don't become reality.
[1] http://cra.org/govaffairs/blog/2012/04/undergrad-computer-sc...
[2] http://www.bostonglobe.com/opinion/2013/03/30/visa-program-h...