[amelius]

The whole point is that these services could be provided by other service-providers. This is like a car of brand X that only accepts fuel of brand X (except now it is a service like internet or an API).

(No pun intended with the X)

[yreg]

You can use your own internet connection, the car connects to WiFi.

As for the API, then yes, if you want to buy a fleet of Teslas and manage them with your custom software, you need to go through Tesla. That API is a service and not a product. The car is still a product though.