Real Madrid president made the grave error of losing Ronaldo and Zidane in one go, then he even didn't bother getting Hazard or Neymar to help the new coach settle in.
It wasn't an error. The president didn't want Zidane to go, but Florentino Perez had no choice but to accept Zizou's wishes (the guy was probably too stressed out to keep being the manager of such a demanding club). Also, Florentino Perez was the one who didn't want C.Ronaldo on the team because of all the scandals surrounding him, so it's not like Florentino made a mistake selling him, it was all planned.
About Hazard or Neymar. PSG was not going to sell Neymar to a potential rival in the CL. And Hazard's price was too high for Real Madrid, I think Chelsea were demanding more than 200m for a 27yo player, that's way too much considering that you have some young talent on your team like Asensio, Vinicius Jr, etc, who need some playtime rather than more competition in the squad.