They abandonat trophies because they need to sell. Not because they don't have a very good low cost strategy in terms of signing the right promising players.
I don't know what your argument is, to make money you need to spend money. You can never avoid the risk completely.
My argument that you aren't making sense.
No club in financial trouble is paying for 16 years old CB in Croatian league before he plays. That is absolute nonsense. Such money is paid for attacking talents that have certain value.
You are using irrelevant example to prove it.
Here is BVB U18 defensive signings:
https://www.transfermarkt.co.uk/bor...=&pos=Abwehr&detailpos=&altersklasse=u18&w_s=
The only one they paid anything for is Sergio Gomez, who was midfielder at the time and it was 3M.
In der Statistik Transferrekorde werden die teuersten Transfers über alle Saisons hinweg angezeigt und chronologisch des Marktwertes absteigend angeordnet.
www.transfermarkt.com
This are most expensive U18 deals. All who were 10M+ were almost 18 at the deal, were either in top 5 leagues or starter with significant game time in their league. Many were busts like Breno and Bitshiabu. Luka was an exception (dral agreed in summer 2023, officially joins when he was 18)
And BVB abandoned the idea of trophies, and prioritise money. When you do that you invest in several youth that can produce high sale, because you don't care about trophies.
Barca do the opposite, they invest heavily in La Masia and B team, while prioritising investing possible penny in first team squad to win trophies.
To do both, you need funds. Barca didn't havec12M to spare in 2023