There's a theory that Disney's iron grip on Western animated film during the 20th Century was due to the huge success they had in the Second World War. For obvious reasons, everybody wanted a bit of escapism when going to the cinema, and Disney's fantastical tales fit the bill (and it wasn't like much of Europe could support the sort of economy needed for major animation studios that could compete with Disney after the war was over). This solidified animations reputation of being 'for children', supposedly.
No war means that Europe and America, one way or another, climbs out of the Great Depression without the costly affair of a world conflict and ensuing Cold War arms race. This pseudo-return to the 19th Century Concert of Powers, instead of world-shattering war and follow-up ideological conflict means that Disney would likely have more competition in Europe, and an audience that may be more interested in animation that deals in adult themes (not necessarily gore'n'tits, just topics we deem to be mature).