I'll buy that, especially in NYC-like urban environments where frequency of exposure is definitely not the issue. Suburbs and rural may be different.

Part of the increased diversity is unavoidable due to technological changes eroding previous touchpoints. E.g. limited broadcast TV becoming cable becoming streaming.

But there does seem to be an increasing dearth of the logical tonic: discussion-facilitating diverse spaces. Places where people of different opinions can mingle, there are strong social norms around mutually productive conversation (and enforcement to discourage / weed out poison apples?), and that are open to new people.