There is a difference in signing players for the future and signing young players who are good enough now. Look at Konate at Liverpool, he's 22 and one of the best defenders in the league, Ruben Dias is 25.
We need to be signing players in the 22-25 age bracket, who are good enough to go straight into first team (Kamara for example), that's how you future proof your squad. Not signing two 29 year old defenders to replace your 29 year old.