True, bookmarking UI/UX has been nearly unchanged from the dawn of the browsers with GUI; I guess it has to do with the philosophy of a bookmark i.e. as a digital analog to a physical bookmark in a book, it needs to be blatantly simple. I agree that the default bookmarking experience in the browsers hasn't scaled up well with the Internet, I do have decades of bookmarks distributed across several tools.
The problem you've stated also brings in attention about other problems which may have a role to play in this, namely 'Human memory, lack of thereof' & 'Getting things done at individual level'.
My current workflow to bookmark is of the following order,
1. If the entire content should be easily viewed, then store via pocket extension.
2. If a partial content should be easily viewed i.e. some snippet with link to entire source, then store in notes (Apple).
3. If the content seem useful in the future, but it is okay to forget it; then I store it in the browser bookmarks.
Over all, I agree with this need gap.