The agony of WWII and its collaborators is still within living memory, as is life under the Soviet bloc with its secret police and disappearing people, likewise wars of ethnic cleansing in the Balkans. There are also several large secessionist movements where people actually want to secede, unlike in the US, where that kind of talk is rhetorical[1]. I don't think that kind of blanket statement of 'higher trust societies' can be made; the situation is a lot more nuanced.

For that matter, I think that Americans had a lot more trust in their government before the last couple of decades.

[1] https://en.wikipedia.org/wiki/List_of_active_separatist_move...