Age caught up with them. Juanfran, Godin, Felipe Luis, Gabi and maybe Torres too aren't fit to the task anymore. All in their 30's. Only at Juve can you relive your prime in your 30's
Same goes for Real, Ronaldo can't carry them anymore. Marcelo and maybe Modric too need to be replaced shortly. Just shows how important it is to replace players at the right time.