But the very strict policy as you say doesn't apply all the time, does it? Modric is still playing there and they had other players above their 30s thatgot their contracts extended in the past. In my opinion, if a transfer like this would be made by Real Madrid, they would only give short term contracts and have some backup idea in their minds because they don't want to run into problems when they have a situation like Carvajal and Alaba being injured during the most important time of the season.
However, I doubt Van Dijk would be ok with signing a short term contract with any club now. He probably wants a two year contract at least, if not a three year contract and neither Liverpool nor any other top club would be willing to give him that contract and I understand that.
For Van Dijk being a free agent is the best that could happen to him. Any fees for signing a new contract go straight to him as Liverpool wouldn't have to be paid a penny.
Yep, Real Madrid currently lack of a player with warrior attribute, Rudiger isn't even reach that, you need to have someone who don't mind to fight against other player. Remember the last World Cup, after Leandro Paredes kicks ball to the Netherlands bench, Van Dijk come in and bodied Paredes.
Van Dijk can still play in the top 5 league maybe up to 37-38 years old.
Although Modric is already 39 years old, but he's playing with brain and touch, while playing as defender is harder because they really use their physique.