It's the 'legal system' - and everything else.
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.