There seems to be a lot of concern within Germany that their league(once unpredictable where anyone could win it, especially when Bayern have an off season) is indeed turning into the La Liga of sorts(Real/Barca domination) with how far ahead Bayern and Dortmund(oddly enough, the gap between the two in the league is bigger!) are compared to the rest of the clubs in the league.
IMO, the other clubs just have to spend the money they have/get better, while also looking to poach good young talent across the continent(like Dortmund have done) and the world.
Ofc, this has only been going on for about 3 years now(Dortmund finished 5th in 2010) and could thus totally be a knee-jerk reaction.