Did the FAA or some other agency release a statement saying they were relaxing safety standards because they deemed the increase in risk economically acceptable? Do you recall checking a box when booking your last flight acknowledging you would prefer a few cents off your ticket to a fully staffed ATC tower? Did safety technology suddenly get substantially worse, increasing the cost of preventing failure beyond a red line we set?

Failures will happen, and resources are finite. But the idea that this particular failure is an inevitable consequence of a rational economic decision, that we as a society got together and decided we would permit X fatal aircraft incidents per unit of time, and that there is no point in improving because perfection is impossible, is patently absurd.

No, we have been and currently are willing to pay for fully staffed air traffic control towers to prevent precisely this sort of accident. If you told someone at the airport there was a single controller doing double duty, there's a good chance they would choose to pay a premium to change flights to a time when the ATC was appropriately staffed. There is a reasonable expectation that when you book a service like a flight that you are paying for the appropriate staffing to provide that service. I'm paying for the person who maintains the engines, and the person who audits the paperwork to make sure the maintenance got done, and the engineer who checks that the latest revision won't cause the engine to explode in mid-air, and all the rest of the massive chain of people required for air travel to work as its supposed to. The airline is supposed to set the price such that they can afford to pay all these people. They don't get to make the decision that they can take my money and pocket what was supposed to be going towards engine maintenance because they don't value my life sufficiently. Likewise for air traffic control.