If only they hadn't tried to cut it down to 16 bits near the start, we could have avoided a lot of the partial support that emojis expose.
Seems strange they would miscount so grossly otherwise.
But we currently have 88k CJK characters assigned out of possibly more than 100k total.
I can't easily find anything about how this went wrong and they got such a small number.
If you also count the Unihan variations registered in Unicode's ideographic variation database by various Japanese outfits, encoded using the VS16 to VS255 characters after the codepoint they modify, there's another 8k or 9k unique characters assigned.