Note that this post is of course about high internal dynamic range specifically and the necessary tonemapping that then follows for presenting an SDR image, not about how modern games do actual HDR (but then that should be pretty similar on a high level to the extent I understand anyways).

> In the real world, the total contrast ratio between the brightest highlights and darkest shadows during a sunny day is on the order of 1,000,000:1.

And this is of course silly. In the real world you can have complete darkness, at which point dynamic range shoots up to infinity.

> A typical screen can show 8 (curved to 600:1 or so).

Not entirely sure about this either, monitors have been pulling 1000:1 and 2000:1 dynamic ranges since forever, even back in 2017 when this article was written, but maybe I just never looked too deep into it.

The static contrast ratio (1000:1+) you mention is different from effective perceived contrast after tone mapping - manufacturers' specs measure black-to-white in ideal conditions, while tone mapping algorithms must compress real-world luminance ranges (millions:1) into that limited display range while preserving perceptual detail.