While they use the same script, they are not interchangable. A person from Taiwan would recognize characters in a HK or Japanese newspaper but would not necessarily understands it. A good half would only make sense to someone who speaks Cantonese.
Also, several languages have moved from a script if iconographic characters to phonetic ones: for example Vietnamese and Korean, the former adopting a phonetic western alphabet with accents, and the latter developing a new phonetic script, hangul. Japanese developed two new syllables based scripts, hiragana and katakana, which are mixed with the old word characters (kanji). All these used to use Chinese styles characters prior to the switch.
No reason Chinese couldn't do the same. In fact, it did… pinyin is a formal phonetic alphabet for Mandarin Chinese that's based on the western alphabet with additional marks denoting the tones of the words. It's only hard I'm an educational setting, but you could use it anywhere!
Also, several languages have moved from a script if iconographic characters to phonetic ones: for example Vietnamese and Korean, the former adopting a phonetic western alphabet with accents, and the latter developing a new phonetic script, hangul. Japanese developed two new syllables based scripts, hiragana and katakana, which are mixed with the old word characters (kanji). All these used to use Chinese styles characters prior to the switch.
No reason Chinese couldn't do the same. In fact, it did… pinyin is a formal phonetic alphabet for Mandarin Chinese that's based on the western alphabet with additional marks denoting the tones of the words. It's only hard I'm an educational setting, but you could use it anywhere!