But most pages in Chinese won't be showing all 10k+ glyphs on the same page. Small pages won't have very many characters at all, a few paragraphs would only be a few hundred different characters, so a minimal font file would be on the order of kilobytes. 3k+ characters covers 98% of the text in a common newspaper, that font file is on the order of a megabyte.

I've used FontForge to export much smaller font files containing only particular characters. But there are also ways to store char fonts in json using libs like typeface.js and cufon.