Vieira said: At that time, the situation at Real Madrid was very complicated, and I doubted my position there. Real Madrid's neglect of Makelele makes me worry that I will follow in its footsteps, which scares me. Actually, I should have joined Real Madrid. Now, I don't have too many regrets about my career, but if I can, I hope to change one thing, and that is to join Real Madrid decisively.
So the main reason why Real Madrid failed to sign Vieira was that Vieira himself didn't want to go at that time.