It only existed for pizza -- easy to deliver to many recipients on a run -- or local bike courier in dense cities.

When every restsurant delivers separately, and the delivery agent isn't based at that restaurant, the economy of scale vanishes.

This isn’t a mystery: we inserted a middle-middle man who extracts their own chunk of change.

Very very expensive middle man. Which for long time was only concern about minimizing costs in the delivery, but not at any other part of business.

We stopped exploiting high school kids?

Why is it exploitation for a high school kid to have a part time job? Teaching youngsters the value of a dollar and giving them some life/work experience seems like a good thing to me.

By paying them prison wages?

They didn’t make any less than any other service industry worker.

The scam was getting them to use their own vehicle without mileage fees for depreciation. But even that’s gone now with lots of pizza places having a fleet of delivery vehicles for the drivers.

To your snarky meta-point, yes, having people learn the market rates for labor is a good lesson. It’s really good for teenagers who don’t actually need the money because it’s about the lowest risk hands-on way to figure out that life is harsh to people who have limited skills for where society pours its money.

Because teenagers are much better off staring zombie like at a screen, instead of earning money providing a service for people in a task that requires at least a little social interaction.

Expiry of near zero interest rate.