A deal bringing Amazon Prime Video to Apple TV, announced on June 5 at Apple Inc.’s developer conference after years of talk, shows how competitive tensions among Silicon Valley titans can stand in the way of serving customers.

The logic of linking Apple TV, a device for watching television over the Internet, with Amazon.com Inc.’s booming video-streaming service looks obvious.

Apple needs great video to sell its TV player. Amazon needs places to stream its TV shows so that people sign up for its Prime club to watch them – and buy more toilet paper, too. Viewers want to watch their favourite programmes on whatever device they choose.