One factor in this may also have been the way the privatization of East Germany was handled. Its often overlooked, but the vehicle for it was called Treuhand[1]. Regardless of whether it was necessary or not or right or wrong, it did basically shift out a large amount of capital assets into West Germany (and still carries this sentiment of "opportunistic theft" today).
[1] https://www.sciencedirect.com/science/article/abs/pii/S01475...