About this 50m rumors, imo: his knee is probably in a very bad state.
That means that his future at the highest level is a gamble:
1. he could heal and play at the highest level for 8-10 years
2. or he could turn into Vermaelen or Puyol from last years when he will have an injury after injury.
He will have a few good Months, then another minor knee, muscle or groin injury due to not playing.
Then he'll need a few weeks to return in form and then he'll get injured again.
So, to some extent:
Pique is injury free and he can play for 2-3 seasons more.
Lenglet is young and injury free and he can play for 10 years more.
De Light is young and injury free and he can play for 15 years.
So, relying on those 3 is not THAT bad.
Also, we can always buy a new CB when we'll need, since we have bought 3 different CBs in the last 3-4 summers (Umtiti, Lenglet, De Light).
Plus, we have tried with Mina, Marlon, Murillo, Todibo in between.
So, not only:
1. that we can buy someone like Lenglet in 2-3 years
2. but maybe one Todibo/Marlon experiment will work out one day and we'll get a cheap 4th Cb