I was intending to address your statement specifically about lack of real income growth, not any underlying causality with degrees. I brought it up because it is often stated as fact here in the US, and has a large impact on Collective sentiment, but is not reflective of reality.

I agree that the topic of education is much more nuanced. There are obvious factors such as the types of degrees, their utilization, and ultimate productivity that need to be taken into account. Less obviously, there are factors like the changing composition of national production it's relative specialization with respect to the global economy. Please make it necessary to evaluate the impact of Education against a counterfactual where education is held constant at a national level.

Similarly, I would argue that the education to outcome statistics that are often trotted out are misleading due to uncontrolled confounders and intrinsic differences in the groups that go on to receive various levels of Education. That is to say, there are likely many differences between the average person that gets a post-secondary degree and one who does not complete Primary School besides their educational attainment.