In the case of Korean typefaces, there are tools that help expedite the development of Hangul characters. As Korean syllable glyphs are divided up into component pieces, one can instruct the tool on where to place those components and which variant of each component to use. For some fonts there are 40+ variants of each component! With this sort of tool, building can be faster. But it won't always work for a given situation and then the work has to be done by hand.
In some Japanese foundries, there is something of an ‘toolkit’ that is used with examples of the different kinds of strokes necessary for Kanji. So the digitizer (more on that later) can just drag in the one that is appropriate for a given glyph. However, as each glyph is different, there’s still quite a bit of manual tweaking necessary from there.
Part of the problem with Japanese and Chinese is, like with Korean, there’s significant manual adjustment of a given radical or stroke for every character. So even if a tool was able to at least ‘assemble’ the pieces into a given glyph, you’d have to make significant manual adjustments from there.