Bulletproof your career with Lean manufacturing and Six Sigma methodologies

There used to be a time when certain jobs are considered as dream jobs and highly respected such as Telecom new connections and ticketing clerk in a reservation counter, teller in banks. These were all niche jobs and posts. What happened to those jobs? Are they still in demand or the demand has reduced? Many of those who did not want further learning or skill enhancement were left behind as clerks with same pay or lost their jobs.