It doesn't seem like an amicable parting. You never want to have a guy like Carmack just leave. He's a giant in your industry, he's popular and highly respected

It doesn't seem like an amicable parting. You never want to have a guy like Carmack just leave. He's a giant in your industry, he's popular and highly respected and you gain a lot by having him be associated with your company. So at the very least you give him a honorific title and invite him to all the corporate parties. It didn't seem like this happened here.