Likely one of the reasons Japan still uses its traditional scripts is that Japan has historically maintained a relatively high literacy rate dating back to the Tokugawa shogunate[1]. There's never been much of a push factor into simplifying the script, since the educational infrastructure is in place to teach the script to the vast majority of the population. By contrast, countries like Turkey, the People's Republic of China, and Vietnam had very low literacy rates when the government started engaging in mass literacy campaigns, creating an incentive to simplify the language since most people didn't know the traditional script anyway. Obviously, in all of those cases, there were ideological reasons for replacing those scripts as well
> There's never been much of a push factor into simplifying the script
No, actually there was two pushes in modern times. One advocating the use of romaji (or even French) which did not succeed.
Then there was a set a post-WWII reforms that aimed to simplify the script by: standardizing kanji use (eg 言う instead of 言う or 云う), standardization of kanji readings (当用漢字), kanji stroke simplification (新字体), dropping the old kana usage (旧仮名遣), standardization of kanas themselves to get rid of 変体仮名. The convention also shifted from using katakana everywhere where kanji are not used to the mix of kanji/hiragana/katakana of today. So yes, the Japanese script changed quite a lot recently.
[1] https://en.wikipedia.org/wiki/History_of_education_in_Japan#...