In high school and college the steps in learning Japanese were for me Hiragana -> Katakana -> Kanji in short groups.
I'm curious as to why they simplified the characters for reading and writing, but also retained about 4500~ Kanji characters for written purposes and even to this day names.
With as intelligent as feudal and current day Japanese persons are, why create a visually simple and in some what lower learning curve set of writings other than Kanji? Was it to better self identity the Japanese written language or what?
I can over from the Peter The Great Cyrillic vs Latin Alphabet post, and didn't want to hijack it more than I did. And now my curiosity is bubbling!
This is really more a question that belongs in the linguistics subreddit. Also, I don't have access to any formal sources right now, but I can give you a general response.
The Japanese kana evolved out of the Chinese kanji over a long period of time, a process that started early with the use of man'yougana (the Tale of Genji is an example) and was not fully completed until after World War 2, when the particles わ/は wa and を/お wo were restricted to は and を.
Man'yougana, like the two modern kana, only represent sound, not meaning. The reason these were necessary for writing down Japanese is that while Chinese has no inflection, Japanese verbs and adjectives do and in order to visually represent this, man'yougana were used. Again, the process from the earliest man'yougana to the modern kana took centuries, and there were many different kanji used to represent the same sounds until efforts were made to standardize it somewhere after the Meiji restoration.
The reason that kanji are still used alongside kana is that they made texts easier to read. They break up the sentences, and make the intended meaning of words clearer, which is useful for a language that has a restrictive phonology like Japanese.
I hope that clears things up a bit.