I've heard entirely the opposite, that having a close relationship between chip designers and fabricators allows for higher performance designs. I don't know o

I've heard entirely the opposite, that having a close relationship between chip designers and fabricators allows for higher performance designs. I don't know of anyone who interpreted AMD selling off its foundries as anything other than severe financial distress, and it worked supremely well for Intel while they stayed at least one step ahead of the competition. Enough so this is said to have wiped out a generation of CPU architects while Dennard scaling still worked, no matter how clever they were, Intel moving to its next process node wiped out their speed advantage. But it's a brittle model, if a company screws up a node and is too messed up to handle the failure gracefully, as Intel is doing with their "10nm", no doubt with pride as a factor. And it's not uncommon for institutions to permanently lose abilities, I'm not counting on Intel succeeding with their "7nm" node. On the third hand, we're now down to 2-3 high end CPU fab companies, Samsung, TSMC, and maybe Intel. That also can be a brittle thing.