“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?)”
While I’d agree some markets could become ‘saturated,’ I’m not sure that means opportunities in those markets would ever completely dry up. Take sports venues for example. I don’t have a lot of comparisons, but I would say the venues here in Cincinnati already use signage to a high degree. There may not be new opportunities at those venues for additional signage, but there is always opportunity to upgrade/change the existing signage. As those venues compete for the entertainment dollar of the consumer, upgrading gives them an edge over competing venues. Keeping up with the technology is common among many verticals: retail, food service, entertainment, etc. Keeping it shiny keeps the customers coming in.