Likely this hasn't been done because it would require many very difficult, "subjective" decisions to be made i.e. which font, line-spacing, photo-viewer UI, etc.? Better to make no decision at all than to spawn a few dozen endless committee debates.
By contrast, corporations can more easily make these sort of decisions – by fiat – which is why native app frameworks are more "opinionated" / make more design decisions for you out of the box.
This topic is as much the story of two historical forms: the operating system GUI and the World Wide Web hypertext project as it is about two organizational forms: hierarchical corporations and decentralized design-by-committee non-profits / multiple competing corporations.
By contrast, corporations can more easily make these sort of decisions – by fiat – which is why native app frameworks are more "opinionated" / make more design decisions for you out of the box.
This topic is as much the story of two historical forms: the operating system GUI and the World Wide Web hypertext project as it is about two organizational forms: hierarchical corporations and decentralized design-by-committee non-profits / multiple competing corporations.