Over on the Kamado Guru forum I once asked why Kamado Joe fireboxes couldn’t be made as two piece units, since they kept cracking, and Andy Scalzo said that it would take too much in the way of resources to develop such a thing:
If ever there was a reason for me to want to get a KK grill over the other ceramics, this is it. On the one hand, Dennis has put the effort and resources into designing a firebox that will stand up to high temperatures without cracking. On the other hand, we have a business model that would rather replace a less than optimally designed part instead of redesigning it to work better.