Because as a youth team player, unsure as to whether you are going to even make it at your club or break into the first team, the manager who hands you your 1st team debut, you will forever be indebted to them. Many of these players supported their clubs and as you can imagine, the moment they ran onto the pitch, be it the Camp Nou or Alliance Arena in front of thousands of fans, to play with some of their idols; was probably the best moment of their young playing careers. Doesn't mean they wouldn't have made it regardless, it just means he threw them in before anyone else. that is the no.1 thing for a academy player. Believing that they are gonna have a career at their club. And when they start playing for the first team, it all seems real and worth it all.
There are videos of Zidane honouring Jean Varrud who gave him his debut at Cannes. All players should honour the guy who gives them their debut and many do. A lot of the time debuts are given just as a run out to see what the player can do, or injuries as in our case, but for the player it is massive to them. Souness gave debuts to Steve Mcmanaman, and Fowler, Dalgliesh debuted Jamie Rednapp and Roy Evans debuted Gerrard, Michael Owen and Carragher. I wouldn't say any of those managers started the process for Liverpool's treble, future title challenge or champions league win, they just handed young prospects their debuts which tends to happen when you have a decent academy.
