European sales are sluggish I agree, and they will get much much worse.
However a bigger cause of this is the SUVs, 4x4s and commercial vehicles that aren't being sold in the USA. Factories are having days slashed off their working weeks, across the board and this will continue for some time. R&D for these cars, plus the expensive US employee and pensioners costs are hitting them hard. Same with Ford.
European operations for both Ford and GM are in relatively good shape, all things considering, however they both failed to get their Middle East and Asian divisions going in any meaningful numbers compared to the Japanese companies so they are not as diverse.
As I said, sales are slow in the Western part of the world, this will not change for quite a while. However even if sales are slow, they will still have a large market share.