Why so many delivery startups? Are these real problems needing solutions or entrepreneurs chasing the perception of a market that, in reality, does not exist?

Why so many delivery startups? Are these real problems needing solutions or entrepreneurs chasing the perception of a market that, in reality, does not exist? Quick story: A good friend of mine thought he saw an opportunity to make money when 3.5 in floppy disks came out (yes, this is ancient). He found a supplier of bulk disks and placed ads in several magazines offering 50 and 100 disk packs at a good deal. One of the magazines printed weekly. A week after he placed his first ad a competitor came out offering a similar deal. A couple of weeks later, another. And then another. And so on for several weeks. At the conclusion of his agreed-upon twelve week run for the ads he did not renew the contract. He sold exactly ZERO disks. He watched as every single one of his competitors pulled out as their contracts ran out. His conclusion was that these entrepreneurs simply followed each other into a non-existing market. He was first. Others saw what he did and thought there was money to be made. They all followed each other taking a virtual dive off the edge or a cliff. Nobody make a dime. Ever since he told me that story years ago I've kept an eye out for that kind of behavior. I've seen it many times and in different industries, some with massive capital investments. One such example is the consumer 3D madness that keeps coming back to bite those who try it. But they keep trying! Amazing.