In my experience as a self taught coder and also as a teacher of many coders, learning to code is easy but learning how to code efficiently and effectively is hard and takes many years of practice.

Every now and then (just for fun) I look back at the code I wrote 10 years ago and just think 'Ugh ... did I really write this' ?

More to the point, building a robust product (think: bug free) requires a significant amount of coding skill - I seriously doubt that anyone would be able to achieve this from scratch (at least, not within a reasonable time period).