I would go a step further and say you know what you have after a QB has 6 losses on their record. If they can't meet the minimum standards after 6 losses, they need to ride the bench and develop. Keep them around for another shot IF the next QB racks up 6 losses and also fails, and you believe there's enough potential to develop them. After 12 losses, you have to move on from a QB if they can't demonstrate the minimum standards of a playoff caliber QB.
It's not difficult to see a playoff level franchise QB on a bad team. QBs should always elevate their offense and make their players look better than they actually are on Sundays. It's the opposite with the Panthers. The WRs and RBs are making Bryce look better than he actually is at this level.