1. Academics write and submit papers -> university/tax money pays 2. Academics review papers -> university/tax money pays 3. Academics organize and attend conferences -> university/tax money pays 4. University buys published paper from publishers -> university/tax money pays
So university/tax money pays for writing the paper, quality assurance via reviews, conferences, just to finally buy the paper via some insanely expensive subscription.
For a rational environment like science this model is simply insane.