They understand well at Valve they must foster a community around their devices in order to give them a long commercial life-time. They can’t afford/don’t want to design new controllers to release every 2~3 years. Also, many will be willing to pay more for a device that is part of an ecosystem, having a community and 3rd parties creating this ecosystem for no extra cost it a complete win for them, it’s also a win for consumers twho get to do what they want with their purchase.