>>4334577Because they are designed by the japanese and they are a culturally anti-innovative people.
We know that if whenever you would shoot at the ISO just before the sensor switches to another gain circuit, if you push from base ISO instead, the shadow detail and noise look the EXACT same, but you keep the same amount highlight detail as base ISO. The japanese designers also know this. But that's not how cameras historically worked. Historically, faster films had less dynamic range, so when the camera is in faster film mode it needs to have less dynamic range. They COULD just automate this process and make ISOs besides the gain stage switches fake, just metadata instructions for a different tone curve, but they won't, because that's not how cameras are supposed to work so they apply the gain before writing the raw and blow the highlights and crush the shadows. Anti-innovative.
On the zf for example there is 0 benefit to going above ISO 800. Once you hit 800, just push exposure and enjoy your highlights. It's actually worse if you go over 12800 natively because that's when raw NR kicks in. In theory, deep space astro levels of stacking could reveal slight differences but they're not relevant to photography. But the camera will never have an option to work like this, because that's not how cameras traditionally work.
