Many of them will be approached by other clubs. It´s not onnly about money but primarily there´s no project in the B team. Buying loads of non La Masia players for the B team is stupid.
I dont care if they play in 3rd division. Busquets and Pedro played there with Guardiola.
What i see in the B team is 10 new players each year from outside La Masia.
It´s obvious that these players get frustrated with no future in the horizon. And then they leave like Mboula, Bernabé, Garcia and Gomez.
All of us want to believe that. Blame it all on the board. But it's not really that way.
I'd say that they go for 2 reasons:
1) money
2) better chances
1) money: Many of them (most) won't make it as professional footballers and they'll try to get as much as possible. Garcia left for huge salary. Do you think he has better chances of making it there? With Stones, Laporte, Otamendi etc. all young than here? I doubt it.
2) better chances: Gomez here was supposed to play with the B team while in Borussia he can compete for the squad. But we simply can't give him those chances. Borussia is not fighting for the title seriously and their business plan is based on selling promising players. That's how they operate.
Some players, like Mboula, weren't even willing to try their chances. He would play for the B team in Segunda but decided to go. Hasn't done anything significant yet.
But, it's all true about buying useless players. I agree with that part.