Terraria does not rely on steam features in order to engage with its core functionality. Perhaps you are trying to imply that the error is in the developers having integrated their publishers features into their release in such a way that a hard dependency on the runtime is formed when it shouldn't be.

This is not a valid argument because whatever calls terraria is making to the runtime should have a fallback in place for when the runtime is not being used. That fallback should be implemented by a small dummy runtime or something. It shouldn't be on the devs to ensure their single player game works when the publisher's adware bloated garbage runtime stops working.