A lot of the ill will sentiment is down to Berlin Zoo shareholders .... (bulking in cash and a good source for Berlin Zoo to survive financially without Municipality...). Some of them have yet to come to terms with the fact that Berlin is now a city of shared histories where East Berliners do count and have their equal place and base in Berlin Capital City. Unfortunately, as you so rightly put it, consequently the Tierpark Berlin sometimes suffers unduly... I really, really would hope that the orang utans will eventually get a spot in Tierpark (which I know ... is probably remote and absolute wishful thinking on my part).My 2 cents on the matter is that the Capital facilities are quite able and known how to move the animals in both facilities, but there's different stakeholders that go in the way: heritage and historical buildings/structures (which I also like), economic difficulties and human pride on both the zoo and sustainers' side, to maintain a legacy of symbol-animals which means spending more to upgrade something that could be built cheaper/easier on the sister facility's site.