Why does owning the device not yet mean I can access the data it generates?

The EU Data Act applied on September 12, 2025, giving users a legal right to access all data generated by connected products in real time and in machine-readable formats. But the regulation specifies no common API shape, no authentication handshake, and no wire format that developers can build against. Car manufacturers, health device makers, and smart appliance vendors are each building proprietary implementations, or nothing at all. The second compliance phase, requiring devices to be designed for data access by default, arrives in September 2026 with no standard for what that design must look like.