Any other top club would've been preferred to strengthening up the already monopolistic big dog of the Bundeslolga. Why even compete anymore? Just give the dinner plate you call a trophy to Bayern every year, because even if they don't win it, they'll make sure to strip your team bare of any chances you had of becoming a second power in the league.
You talk like Bayern has become this good because of signing Dortmund players. And yet we had our most successful season without a single Dortmund player in our squad. Where's your logic.
And transfers, like it is any different in other leagues?
Juve: Buffon, Chiellini, Ogbonna, Simone Pepe, Vucinic, De Ceglie, Peluso, Bonucci, Padoin, Pirlo, Quagliarella, Isla, Lichtsteiner, Asamoah
Real Madrid: illarashit, Ramos, Diego López, Isco
The only difference is Real Madrid prefers to buy stars from other leagues and splash big money, because usually those players have more marketing potential.
Bayern prefers to buy from Bundesliga because the players know German already, are used to the culture and weather, and are proven in the league. And prices aren't inflated
Take a look:
Yurt posted it a while ago. Bayern team core is homegrown, unlike most "top clubs". That's how success is built