This could easily have as much to do with support costs as anything with the technical side of the protocols. A member of my family works in customer support f

This could easily have as much to do with support costs as anything with the technical side of the protocols. A member of my family works in customer support for a company making devices using both zigbee and thread, and claims that support calls for debugging zigbee are often among the longest (and thus most expensive) calls they handle. Unsure what IKEA's tech support looks like, but I assume that most issues not solved by support turn into returns, which are also bad for the bottom line.