Based on the top Substack authors, there is an audience willing to pay $5/mo for low effort opinions based on other people's investigations.
In a sense ProPublica won. Its mission is to do real investigative journalism and get as many people to hear about it as possible. They are winning when people take their X and repackage it into dumbed down Y. They coexist with the low effort Substack ecosystem.
Even if zero people pay for 404 Media, who is going to be like, "oh man, these guys cracked open the Right to Repair story, I should hire them." That sounds like teeing yourself for content marketing at iFixit at worse, Microsoft at best. Why?