Many said the same about the likes of Caldara and Demiral too, even Rugani when he was young and hyped with lucrative offers from abroad that we turned down, and look at how these turned out… hindsight is a powerful tool.
We can’t keep all of them when they are inconsistent or still raw, some develop much later in their careers and in the Juve environment most often than not there is little time or space for grooming, while also taking into account that many ask to leave themselves either for the money or more guarantees regarding playing time, which we can’t always provide.