Germany is a very stable robust economy that might be their #1 'export source' - there's a lot of related knowledge - and in a 'cramped Europe' - the Berlin area is wide open.
FYI Berlin has 'wide avenue streets' which are totally unlike most other European places, sometimes it feels like Los Angeles and not Europe.
It might have been possible to go to Czech/Poland but there are just a large number of 'little things' that can go wrong over there, issues best left to those who know and operate the market well.
Compound this with the probable politics of the game and it makes sense.
In a way it's the most obvious choice.
There are ways yo try to "hack it" like subsidies or having personal relations with someone high up but I don't know how cost effective and long term they really are.
So if people want long term improvement, they should vote for a strong legal system instead of "I personally brought this factory here".
German/French car companies, with long and historic ties on many levels to say, Poland, can fathom the risk of going there, especially with a long term view.
Volskwagen can plan decades ahead in some facets.
It takes 'a whole team' i.e. government (local, Fed, EU), probably financing/banking on both sides, political buy-in etc..
But for a new US company to go to Czech ... is asking for trouble.
The difference between E/W Europe is definitely centred around competitive advantage and long-established industries - but I'd argue more than anything it's 'good governance' at every level, private and public. And it's the same all over the 'developing' world.