How can it be "a failure of Unicode's mission" when the mission does not really include that? The foremost reason that Unicode exists is the unification of tons

How can it be "a failure of Unicode's mission" when the mission does not really include that? The foremost reason that Unicode exists is the unification of tons of existing legacy character sets and encodings and not the technologically perfect system. There are enough duplicates and invisible characters in a single character set (yes some have duplicates by accident or design), across multiple character sets (so you like to map Latin A and Cyrillic А to the same character while retaining the collation order for each case...), or simply necessary to multilingual systems that jeopardize any attempt to "perfect" it. Granted, there are several failed experiments (e.g. interlinear annotations which are completely obsoleted by markup languages) and several pain points (e.g. shrug Emoji) inside Unicode. I don't really like them, you may not like them, but how would you make such a system without all these interim works?