What is the interrelationship of the three post-school outcomes (postsecondary education and training, employment, independent living) identified in the Ohio IEP in regards to a high quality of life for the individual with a disability?

What is the interrelationship of the three post-school outcomes (postsecondary education and training, employment, independent living) identified in the Ohio IEP in regards to a high quality of life for the individual with a disability? Why is the employment outcome considered the umbrella in which adult living/ community participation goals fall under?