It makes sense for an industry to grow if the consumer base is growing. E.g. maybe all these home-cleaning startups make sense because a whole lot more people are now getting their homes professionally cleaned than were a few years ago.<p>But how can advertising &quot;consumption&quot; increase in the same way? Either people buy more stuff (unlikely, because people already spend all of their money on stuff), or advertisers spend a bigger proportion of their revenue on advertising (which also seems unlikely, because their business models haven&#x27;t changed). It seems more likely that most successful advertising companies are making their money by cannibalizing the rest of the industry. In which case, why is the industry growing?