We need an anti-tethering law. After purchase of the device, there should be no tethering by the manufacturer. Otherwise you bought a service and not a product.

Any service you decide to run on the device, should be possible (without explicit approval of the manufacturer) to be provided by any company. The current situation is like you bought a TV and you can only watch the TV-network of the manufacturer.

Needless to say, within this law it should be allowed for any company to perform repairs too, or provide hardware extensions, etc.