The question of whether formal education has ceased to be an effective lever for socio-economic achievement in modern societies and has been replaced in that function by social capital derived from social background is a hotly debated topic of modern social sciences, especially in the Western sociology of social stratification. This study examines the question on the basis of nationally representative data from research conducted in Poland from the 1980s to 2019. We analyze the trends in relative intergenerational class mobility, educational inequality, returns to education, and the interactions between background, education, and destination known as compositional effects. We especially consider the postulate that the direct influence of social-class background (origin) on class destination has lessened over time due to the growing number of individuals attaining higher levels of education. Overall, we observe no indication of a decreasing level of forces of ascription in Poland over the last decades. Our analyses also provide a cautionary tale about a long-term trend of decreasing effect of social origin on destination across educational levels that was found in other countries. In Poland, the effect of parental background clearly does not disappear for tertiary degree holders.