It's strange how players get written off at such a young age now. The dominating Liverpool teams in the 70's and 80's would routinely give debuts to players from the lower leagues in their early 20's having given them a chance to grow and teach them how to be a part of their team first.
Ben Reeves needs to be given time and further chances on loan to play first team football before we can really judge his true potential. He may not be fully grown physically yet, his body may still be adjusting and 'mapping' itself to perform. Peter Crouch needed time before he developed to his potential in his late twenties, he only started to show his true worth at the age of 23 with us.
I'm willing to reserve judgement on the lad, I think you are being a bit harsh. But of course, we would both love him to succeed in Saints colours.