Explain the importance of social inclusion of older people

For the people (and we shouldn't be thinking "them", but "us" - we all hope to be older one day!)

this means a better quality of life when old, and also potential longer life and longer health: with more social stimuli, the brains will be longer healthier

For the society:

lower costs of care (since the elder will be longer independent) and the possibility of benefiting from their experience!