Implicações "de esquerda" da teoria do sinal aplicada à educação?

Leftist Lessons of The Case Against Education, por Bryan Caplan:

This strikes me as particularly unfortunate because there are many results in The Case Against Education that leftists should appreciate. Starting with…

1. Lots of workers – especially less-educated workers – are paid less than they’re worth. (...)

2. Lots of workers – especially more-educated workers – are paid more than they’re worth.  (...)

3. A lot of education is meaningless hoop-jumping. (...)

4. The education market is inefficient. (...)

O que eu escrevi há uns tempos sobre a teoria do sinal - Há prejuizos sociais na educação?