> Turns out people really like being able to just drag-and-drop an image from their camera into a website - being forced to re-encode first it isn't exactly popular.

That’s a function of the website, not the browser.

> That’s a function of the website, not the browser.

That's hand-waving away quite a lot. The task changes from serving a copy of a file on disk, as every other image format in common use, to needing a transcoding pipeline more akin to sites like YouTube. Technically possible, but lots of extra complexity in return for what gain?