I wonder if part of the problem of integrating coding classes into schools is that anyone who has the ability to teach coding could probably get a much higher paying job outside of the school. So the quality of instruction in middle/high school isn't very good.

In middle school one of my friends installed the shareware version of Doom onto several computers and the teacher had no idea how to uninstall it. So we were able to play it when she wasn't looking. In high school, my QBasic teacher left half way through the semester to check herself into a mental institution, and the school's follow up course, introduction to C++, was cancelled since only 4 people signed up. There just wasn't good instruction, and I think that led to there being lower interest. However, I only have my own data points to go by.