A distinct lack of products to work with.
The concept of "scenes" – where you pull together a range of actions such as unlocking a door while also turning on lights and a radio under one name like "Arrive Home" – has been a mainstay of smart homes for at least a decade.
"Scenes" also represent the biggest hurdle to effective smart-home management: how to make different products work together in a seamless fashion without forcing consumers to spend hours creating them.
By insisting that anyone who wants to work with its HomeKit system follows its hardware and software requirements, Apple is in a position to create a simple and polished interface that just works.
Federighi announced HomeKit two years ago at the same conference.
But Apple's decision to do a u-turn and insist on sticking its own hardware in other manufacturers' products caused an immediate cooling in the relationship: one that has yet to recover.