As well the for the majority of the population, writing software is just not attractive it's what technical minded people do, which is 10% of the population at best. Couple that with the fact that the industry up until now has not been that attractive to females and you start to see that there are a bunch of technical and cultural issue working against coding becoming the next mass profession.
The majority of people look at a logic puzzle and see frustration, they don't see a challenge that is interesting to solve. The minority that do, have the spark that is needed to code. Figure out how to give everyone that spark, and you may have a flame, but you still have to deal with all the other issues once you get the fire going.