When we lost the likes of Lowton (2012), McDonald (2013), Maguire (2014) and Murphy (2015) we weren't in a position where we could say we were moving forward as a club. We need that if we're going to keep younger players, they have to feel that we're a club where they can improve their careers and achieve more in the game. When the mentioned three left disappointing seasons were ahead, and I doubt them staying would have been enough to change the outcomes. I don't think they regret their moves.
Things are very different now as we currently have the biggest momentum in English football and are clearly moving forward, mainly thanks to Chris Wilder, but things are looking good in all departments of the club.
Let's also hope more future targets realise what is happening here and choose us over other options, for football and career reasons.