What are the theoretical economics of yeast based or synthetic food based nutrition on a global scale? The chemicals need to come from somewhere. The synthesis

What are the theoretical economics of yeast based or synthetic food based nutrition on a global scale? The chemicals need to come from somewhere. The synthesis equipment needs to come from somwhere. As I understand it growing things in dirt is pretty efficient? Where is the cut-off point when test tube grown food is economically more viable than dirt based alimenation? I am not saying these things wont happen. But we are not there yet. How soon? It took a few hundreds of years of tweaking for steam engines to actually make an economic difference. It took a hundred years for the offspring of babbages difference engine to become the instruments of the cultural and economic transformation they are today. Today, we are locked to dirt. In five years, most food is dirt based. Probably still a decade or two from now. Most analysts predicitions turn out to be pretty bad - but it's their 'editorial view' of current events that I find most educating if done well.