Earlier quoted context omitted.
Substack is literally a paywall as a service platform for indie writers.
They let each indie writer choose whether there will be no paywall, a partial one (for some articles), or a full one.
People are resentful about the paywall at The New York Times, which feels like they took something away.
Somehow the average Substack seems like they are giving away a lot for free but you can get even more if you support the creator. It helps that the creator is in charge of what requires payment so they can use the paywall to help, not hinder their personal brand.