According to press reports, "experts" of the Deutsche Rentenversicherung have calculated that Germany's public pension system is not in fact a bad deal for the contributors.
Specifically, an average income-earner retiring between 2030 and 2040 will receive a return of 2.8 % (male) / 3.3 % (female) on the contributions made.
Nobody tells us what the assumptions are. And the assumptions (inflation, real income growth, number of contributors, taxpayer subsidies) are crucial. The calculation results are completely meaningless without knowing the assumptions.
I tried to find the study on the website of Deutsche Rentenversicherung, but it doesn't seem to be there. Or maybe they are hiding it in some obscure corner of the website.