“Which market segment is the one that is totally saturated with digital signage five years from now? (Is there a market where the gold rush is over and every new opportunity has been already taken?)”
I don’t believe that any market segment is currently saturated, although the retail sector is certainly heavily represented with digital signage. If I had to project a future segment where new opportunities might be limited – it would indeed be retail. However, because of the nature and massive size of the retail segment, where signage experiences constant usage and exposure to customers and the elements, I would project that there will still be a steady replacement and upgrade market.