If industries were personas arguing at a table, Instagram demands pay and threatens to turn off Instagram immediately. Teachers damand pay and can only threaten to destroy society in 50 years. Psychologically, Instagram's threat is a lot more usable, because teachers don't want to pull the trigger on ending society.
In other words, Instagram has a more direct and immediate way of demonstrating value than teachers do.
Australia has exceptional 'productivity' from extracting geological resources, providing exceptional and taxable profits, and requiring few human resources. Low productivity in other areas (e.g., service industries, tech) is more caused by low investment in education than vice versa. Other industries won't find a home in Australia without a capable talent pool, and you can't have that without a well-funded education system.
This doesn't explain why Australia hasn't significantly invested in education in the last few decades.
That assumes that the gains in productivity are passed unto the parents in the form of increased income, do you have any data that shows this to be the case?
But some of the parents gotta be either shareholders or cashed out houseowners?
I just moved from a city where teacher pay has gotten on par with engineers. The only thing needed was outlawing hiring unqualified teachers. Suddenly there was money for teacher salaries.
It didn't solve the housing question for other sectors though ...
The idea of collecting more taxes to benefit $underserved_group is like an obese person eating more to increase muscle growth.