Players like Enzo have zero interest in playing for clubs like Braga.
The reality of the multi club model as it has been used by others, most notably City, is not at all like you are envisioning. It’s not like players are moving from Troyes and Girona to City all the time.
Edit: to start, Enzo wasn’t even starting for River until fairly recently. He would have been thrilled at a big money offer from a team owned by a football power. He wasn’t “Enzo the WC star” then.
That is just a matter of investment and scope for the imagination. What if you made Braga the wealthiest and best team in Portugal? What if Benfica was forced to bid higher and higher against more competitors for their talent and their margins dropped?
And the players playing there knew they were essentially playing for a chance at the parent club, and you paid much better wages than Benfica, and they could earn trophies and CL game experience while developing? City’s model is …. Ok, but it is limited.
Right now we will have to send Andrey Santos out on loan as punishment for buying him early. Because even though there were people in Brazil who said he could be one of their best midfielders ever, he couldn’t meet the “extraordinary talent” threshold needed to bypass the visa issue.
What if we wanted to buy players even earlier? Do we just cede co trial of our investments and “hope” they develop well?
They ARE buying a team in Portugal, and they ARE buying a team in France. They may still buy a team in South America, and really up the ante on control of the talent pipeline.