You are absolutely right: 

Self Discipline, among many other vital life skills, is not taught in the schools. 

Back in the late eighties, I have had the wonderful opportunity to procur and practise the Neuro-Psychology of Self-Discipline, a self-paced and self-directed, audio-video based program, developed by SyberVision Systems, in conjunction with famed neuroscientist Dr Karl Pribram of Stanford University. 

In retrospect, I must say, the insights and techniques from the program had indeed impacted my professional career tremendously in the ensuing years.

Very true!

In other words, without the self discipline as reflected in your commitment and consistency to the endeavour, success achievement is impossible!