I feel like there is a lot of mixture between being an outsider and alienated versus being lonely.

Being lonely has become such a huge factor in (especially young) people's lifes, because they need to hop cities for university and later jobs a few times before they start settling down, that a lot of the friends they make have moved away, or they themselves moved away from their friends and it's hard to find new friends. Sometimes your only new social interactions are at work, and in a country like Germany where work and private are strictly separated at first, this is a double whammy.

It also affects very old people, whose friends have died and whose children and their friends have moved away.

Solitude is endemic in the west.