Billions typically paid for by government subsidy, id est taxpayers. I'm not sure what the justification is for private IP rights when the capital is socialized.

Pharmaceuticals is about the worst example you could pick to make a point. It's notorious for socializing the cost and privatizing the profit (not to mention the ethics of price gouging life saving medication treatments).

Here's what Johnson&Johnson is doing right now with a TB drug whose development was paid largely with public funding:

The pill, called bedaquiline, was first approved in 2012 as the first new TB drug in over 40 years and revolutionized treatment for drug-resistant infections. But its relatively high cost limited access in many low- and middle-income countries hit hardest by an epidemic that still kills around 1.5 million people every year, most of them among the world’s poorest. The company initially charged $900 per course in low-income countries, according to a 2016 report, but gradually lowered it to $340 three years ago.

The secondary patent particularly irked some advocates because the drug’s development was largely underwritten by public funds, according to a 2020 analysis. That study found public sector funds contributed $455 million to $747 million to getting bedaquiline to market, compared to $90 million to $240 million from J&J.