Some people have major debt, medical expenses, family situations etc that drove the original decision. Some people decide to start posting about their car life because why not? But don’t confuse the glitzy social media version of van life for the average experience.
That is if you even notice the stealth campers (to your point). But that’s really the original point - most people don’t notice the car dwelling locals, who spend a lot of their time making sure they aren’t noticed.
People sleeping in cars are also common, and pretty easy to spot since unlike a van, it isn’t common to block out all windows in a car. I’m guessing those are all economic cases.
Looking at social media influencers and assuming they’re a good representation of the average van liver is like looking at a celebrity and assuming everyone in Hollywood is like them.
By that definition me not living in a mansion overlooking the ocean is also a lifestyle choice. I doubt that many people in cities would live in vans if housing wasn't so unaffordable.