Right I agree, the new model does seem quite punitive especially if you don't have an existing business model.
Imagine a new developer publishes a free app without a plan for monetization, and then it goes viral. They would be on the hook for thousands of dollars.
Unless they have a reason to switch most new apps will likely stick to the old model
As threeseed mentioned, most free apps esp. those without a per-install revenue source (e.g., Wikipedia) will likely not use the new model and stick with the old model which doesn't charge per app install
As an aside, look how clear and well-written this web page is. I'm always blown away by how well the whole Apple ecosystem (even the the developer documentation) is designed