Music teaches people to work together, which is maybe one of the most important skills.
Over the years, I've seen how being a soloist and having a family can really work.
You might think that after 40 years of practice you wouldn't need to practice anymore, but sadly it doesn't work that way. You still have to keep chugging away and perfecting.
In a way, the highest praise you could give to a composer like Bach was to take and make your own arrangement; it was sort of an homage to that composer and to his work, so it wasn't considered sacrilegious to do something like that.
Conducting is a strange thing to teach. There are very few great conducting teachers, and most great conductors don't teach. Look at Valery Gergiev - what he does is not teachable. A lot of it is on-the-job training, what works and what doesn't work.