What is it about really old photos that gives people a sense of yearning?
What I think may be the cause is the sense of 'hard times' we feel past generations went through. 'Back then' people had to work, they kept themselves busy with daily tasks, they had to work in order to survive - they did not spend time relaxing in front of the television, on the internet, or hanging out at a mall. Something about old photos reminds us about the ambitious, the attitude that didn't say they'll get it done tomorrow, or they need to sit down and relax before and after a chore gets done.
Philosophically, this seems like a yearning to be in touch with our naturally creative side - creative in the sense of creating, not necessarily artistic. We necessarily must labour with nature as the means of life; not only as a the means of life such as subsistence but as the life of labour itself. The labour itself affords man subsistence, as such we naturally must labour - we are a slave to labour.
What I hope this yearning entails is a yearning for a closer connection with the objects of our labour, as opposed to the alienated objects we create in assembly lines, for people all over the world. The more we produce for someone else, the more detached we are from the product of our labour - we become slaves to the appropriation of another being. They control the demand for our labour that provides an object shipped to someone else, and provides the worker with very little in return. What I hope is entailed in these photos is a yearning for a connection to a non-existent place where the connection between labour and object is not lost.