> I don't think there's a large-enough margin in this space that a new format could chew into to make the general public care

What improvement do you think is necessary for people to care?

Genuinely curious. Spoiler link with my answer to avoid any bias: https://lgms.nl/p/cau/?b64&ZVRNb9QwEL0j9T%2BMKqFtpe1Cqcq9qoT...

Regarding real-world use of WebP - what makes it much worse, in my experience, is that so many web servers are set up to do a lossy conversion to WebP from the original file, most often JPEG (to cut down on bandwidth, or just to satisfy a web speed report originating from Google and therefore pushing Google's technologies). The difference is often very noticeable, e.g. textures smoothed out of existence. Helps to remove WebP from the Accepts header to force servers to serve the original.

It means the technical differences between format, and the real-world choice of which file you want, don't match.

Another interesting niche is in between JPEG and RAW. RAW files are a pain to deal with, but editing JPEGs can be problematic due to bit depth and whatnot. Personally I just want to shoot pictures and not edit/convert/whatever, but sometimes I have a shot that could benefit from a bit of adjustment, and that's where even large JPEGs have an issue. Bit depth and whatever isn't suitable.