Borussia Dortmund's talent scouts are very observant in seeing the potential of a player, and not just the 2 names I mentioned, but if we go back to the past then there have been so many players born from them, including players who are mainstays of Bayern Munich who in the Bundesliga are their main rivals. That is their expertise, but unfortunately they do not use the expertise they have to achieve an achievement and become the best club at least in the Bundesliga.
The scouts at Dortmund are one of the best scouters in football history because they're so good at finding potential top players that are undervalued and not yet noticed by many other scouters and they buy them for cheap prices to train them and resell when their values has appreciated up. They're doing what Chelsea new owners are planning to do but Dortmund does their so well since Chelsea are buying their players expensive but Dortmund does their differently because they don't buy expensive players but sell any players they have at a very good profits. Dortmund can't challenge Bayern Munich because of the resources that Bayern Munich has but growing players to sell for profit is a good way to stay in business while they still play well in the league and get Europe football spots and also challenge in the either of the Europe league to give the club more revenue from playing in this tournaments.