Off the top of my head I'd say this is a novelty comparison at best. People who would never typically buy a digital camera have a phone. Children, the infirme, low income, for example. And then people who do buy a digital camera also have a phone, so that's double-dipping or something.
Further hampering the sales of digital cameras is how snobby and elitist people are in the industry. If you walk into a camera store as a newb they will sell you something, but will hate doing it.
And then there's price, which explains itself. But, lenses can be more expensive than a phone, and I don't think they're counting lens sales into their graph - but they should because phones are a self-contained purchase, most cameras are not. (monthly phone plans and editing software subscriptions cancel each other out)
Don't forget the used market took off twenty years ago with online buying and selling. And old digital cameras still take decent photos, so a lot of people forego a new camera in lieu of a vintage camera just for the aesthetic.
I mean, how many phones could you buy with your kit? Bet it's more than a few. Plus, I think a lot of the preference for smart phones is YouTube has ingrained that GoPro look into the public's mind as normal and aspirational, but most people don't realize these tiny cameras are pretty much the bottom of the barrel for image quality.