Intel has had problems with architectural cul-de-sacs before certainly. But they had other architectures on the back burner they could go back to to recover when things didn't work and they still had their process lead to keep them in the game. Recently, though, Intel's architecture work has been at fine but their process has been the thing having trouble. Maybe they'll be able to get 7nm working properly first try despite the problems at 10nm but I'm not sure given the attrition in their process team after the 14nm death march.