“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 see any segment where digital signage has reached maturity and saturation as yet. Every year, there are new innovations, and every year, there are new improvements – to the point where when you plan your digital signage project/installation, ensure that you’ve planned out the maintenance and replacement of those pieces every so many years, depending on your life cycle planning. Even if you don’t replace it with the same thing, the reason why you installed it or chose to do so in the first place is still likely the reason for the ‘new’ technology to take its place. So while we may see more signage in certain industries and segments than others, due to the technology evolution that we see daily, we will never truly be saturated.