Comment by altairprime

It seems fine to me. Made sense on the first read and matches my experiences with OpenEXR and ProPhoto RGB and pre-Apple monitors.

High dynamic resolution has always been about tone mapping. Post-sRGB color profile support is called “Wide color” these days, has been available for twenty years or more on all DSLR cameras (such as Nikon ProPhoto RGB supported in-camera on my old D70), and has nothing to do with the dynamic range and tone mapping of the photo. It’s convenient that we don’t have to use EXR files anymore, though!

An HDR photo in sRGB will have the same defects beyond peak saturation at any given hue point, as an SDR photo in sRGB would, relative to either in DCI-P3 or ProPhoto. Even a two-bit black-or-white “what’s color? on or off pixels only” HyperCard dithered image file can still be HDR or SDR. In OKLCH, the selected luminosity will also impact the available chroma range; at some point you start spending your new post-sRGB peak chroma on luminosity instead; but the exact characteristic of that tradeoff at any given hue point is defined by the color profile algorithm, not by whether the photo is SDR or HDR, and the highest peak saturation possible for each hue is fixed, whatever luminosity it happens to be at.