There are two separate questions here. (1) Why has society not adopted this over decades and (2) Why do EA people who promote far-UVC not also promote the old technology? The second question has a precise answer.

The patents all expired by 2016, so this contradicts your claim.

I think this was wrong. I don't know where I heard the story about Clinton negotiating price discrimination, but, actually, generics already existed in 2001 before either PEPFAR or Clinton started buying. PEPFAR simply refused to use them because it wasn't actually about saving lives. It switched in 2006 because it was embarrassed by Clinton and WHO using them.

Oster seemed to be aware that PEPFAR was paying 10x as much as WHO, as she writes "Even at generic drug prices." It is a travesty that she did draw attention to this.

PEPFAR wasn't a humanitarian program, but a giveaway to drug companies. It is good that humanitarians stole the money and gave it to public health, but that's no credit to the people who pretended to do charity in the first place. And the cost effectiveness of the project of entering government and stealing money has to be judged by all the people who tried and failed, not just by one project. If this were a real public health project, it would be good to hold it up to tell the other public health projects to be more like it, but it was a sham and telling the other shams to be more like it is unlikely to be effective.

Where do you get the claim about ARVs?

How do you know how many people got treatment? I don't see any numbers in this post or its sources.

Herd immunity is a threshold effect. Since the analyses (correctly!) said that few people would receive treatment, it doesn't matter whether the treatment stopped spread, it would have only small effect on the analysis.

Is there any reason to believe that PEPFAR brought prices down? Why not count Clinton lobbying for price discrimination as economists getting this 100% right? If economists missed the importance of R&D, that's bad, but was it important, or was it just about releasing patents?

So if you intuit that we can do better than peer review, I would recommend getting a PhD in economics under a highly-respected supervisor, and learn how to investigate institutions like peer review (against proposed alternatives!) with a level of rigor that satisfies high-prestige economists.

Wow, that's really specific. Are you trying to evoke Robin Hanson? Before following him, ask him if it's a good idea. I think he regrets his path.

The NYT may be an outlier among papers, but this instance is not an outlier of the NYT approach.

That she is honest is evidence that it was an honest mistake. That she is careful is evidence that it was not.