Although not having been to, nor have experienced what life is like in a developing country; I believe a potential reason why people from developing countries have a more positive outlook on economic growth is due to their strong sense of hope often lined in either their religion or sense of togetherness with one another. When stripped down to nothing of course, by human nature, everyone would potentially come more grateful for even the slightest economic growth as economic growth equals opportunity and opportunity breeds success, happiness and stability. This sense of gratitude is less evident in developed countries as they are already surrounded by potential opportunities to succeed and often forget how lucky they are. 

I believe it is not ones economic growth that improves the standard of living, but the bonds made by people along the way. In saying that, a bi-product of economic growth is often meeting new people through gaining new opportunities... so I guess it has an underlying importance.