The truth really hurts so this post is the hurt locker of posts.
What you call truths others might call an exercise in double standards and ignorance.
e.g.
Kagawa was a player no one knew from Japan who joined a German midtable side. Basically for free. He left for Manchester United. You'd have to be pretty thick not to see the development there.
With Götze we just pretend that his metabolic problems didn't exist, because reasons.
Weigl joined (for €2.5m) from a side battling relegation in the 2nd division. He left for Benfica, could have left for PSG the season before. Can't see the development there.
Pulisic joined as a kid from PA Classics, left for Chelsea. What development?
Hakimi - I don't even know what he's trying to say there, that he's shit because he only joined Inter? Great analysis.
Gündogan - being a regular for City = meh.
Now on to the contrasting examples:
Gündogan, played 1 year at Schalke when he was 8, didn't like it, left. Meh for Dortmund, success for Schalke.
Metzelder played 1 year at Schalke when he was 15, then left. Made the leap from 3rd division football to Bundesliga, as well as the Germany squad and later Real at Dortmund. A prime example for Schalke's youth work, not worth mentioning for Dortmund.
Höwedes: outside of Schalke he played 3 games for Juventus and then moved on to Russia. By the criteria established earlier a real success.
Draxler - Havertz would be a good comparison in terms of hype/promise. Left for Wolfsburg, then for PSG's bench. By the criteria used earlier a real success.
Kolasinac - well if Gündogan is meh, then it makes perfect sense to list him as a succes, right?
Not to mention the players he omitted.
The funny thing is that I doubt many people would even argue that Dortmund's academy has been very productive in terms of top talents since the Sahin/Götze days, let alone be better than what Schalke put out. And what does this have to do with Bellingham anyway? He's not an academy player, neither is he some "nobody" the club takes a chance on like Kagawa, he's a massively hyped talent that can more or less pick his next club. Suitable comparisons would probably be Dembele, Sancho and Haaland.