That is way too annoying, but pretty simple: There are feature requests, but no one is interested in this technique. If you take a look at the “Votes for feature suggestion” livephotos got 23 votes, somewhere down in the list.
I already made a suggestion after wwdc 2017 (1.5years ago), NOTHING: [Feature Request] Support HEIF format in photo library (the standard equivalent to Apple LIVE Photo)
It seems either nobody knows about this technical background, nobody is interessted in, or the people who do are only 23 persons^^
