[faitswulff]

I don't see how your explanation and GP's explanations are mutually exclusive.

To add some detail to this point:

> my understanding is that words in Chinese are largely monosyllabic and involve a decently high degree of homophones.

A syllabary would have had to represent phonetics as well as tones, which would have multiplied the required syllabary by n number of tones. For instance, Mandarin has 4 (or arguably 5) tones. The "ah" sound has four pronunciations: ā, á, ǎ, and à. Hong Kong Cantonese has at least 6 tones, having purportedly lost a few. Different dialects of Chinese have different numbers of tones, and some have been lost or gained within the same dialect throughout history.