Completely disagree with janrein. 99.9% of every flight instructor ever, has used it as a stepping stone to the airlines, the system works and it's well understood. Almost every school would cease to function overnight if you took away the hour building instructors. I didn't start out doing it for love but I did it for 7 years and grew to really enjoy it, and I'd go back to it tomorrow if only they paid tax free long haul salaries
Also, the 1% of people I worked with who were "career instructors" were usually grumpy old
ers, and while they invariably had a great deal of knowledge and experience, their attitude sucked. They had grown stale from sitting in the same office and flying the same circuit and swimming in the same little fish pond for 30 years. They were patronizing and condescending towards other instructors, and loved the fact that the students were all terrified of them.