How do old people contribute to our society?

Now, this is quite an sensitive topic so i will keep this in an third-person point of view. In an country's economy, they are grouped together with children as the non-productive group and they also disturb the dependency ratio of the country. Economically, they are a burden, because they do not contribute to the GDP of the country directly in any way, and are an additional mouth to be fed. Only if we look at this economically. They contribute a whole lot to our society in many ways and are an huge benefit to those who wants to learn from their experiences. Our old ones are able to mentor our youth, because they had gone through times similar to what you yourself have experienced. That somebody who knows the value and purpose of the time he wasted or utilised. They are an source of great wisdom. And they are able to impart their experiences to young fledgings, then young people can learn from them and make changes in their life. In this way, both the society and economy can benefit. There is always an teacher behind an successful youth. The old ones of our time do have an very important purpose to serve. So filial piety is crucial. We need to respect our elders as they are the ones who teach the future generations.