They taught us because they wanted to pass the knowledge on and educate young musicians. It was not because they had to teach because they failed as musicians. There is a huge difference in the reasons why someone is teaching and what they can offer and what they cannot offer.
Don't tell your kids you had an easy birth or they won't respect you. For years I used to wake up my daughter and say 'Melissa you ripped me to shreds. Now go back to sleep.'.