***** NOT A TEACHER *****
I believe that it means something like: They wanted to raise children who were
connected to reality. I believe that the key word in that sentence is "simply."
In other words (I am assuming that the family is the Jobs family or some other
important people), the parents did not want their children to think that they were
better than other people. Neither did the parents want to live as do so many rich
people (fancy cars, many houses, expensive clothes, servants, etc.).
I believe that many young people who achieve fame and make a lot of money often
get into trouble because they start to think that they are special and can do anything
that they want. In other words, they do not lead a grounded existence.
Student or Learner