It's paid out of the taxes on wages of laborers like these engineers working on tunnel construction; when you estimate the expenses for building a tunnel, that'

It's paid out of the taxes on wages of laborers like these engineers working on tunnel construction; when you estimate the expenses for building a tunnel, that's included in the list price - it's just that in USA invoice that line might be labeled "union-agreed benefits" and in Switzerland invoice the same thing might be labeled "government-mandated social security tax" which covers things like "government sponsored" (i.e. taxpayer-paid) pensions.