If you extrapolate the standardization of emoji, and then add a bit of graphic simplification, guess what you get? something like the Chinese ideographs or Kanji characters!
Let’s see if emoji “vocabulary” evolve into a new vocabulary of ideographs, and if the number you need to know how to read gets close to the 2,136 Jōyō kanji (lit. commonly-used kanji), which are the ones taught in school, though literate people usually know more. https://en.wikipedia.org/wiki/J%C5%8Dy%C5%8D_kanji
In internationalization, CJK is a collective term for the Chinese, Japanese, and Korean languages, all of which use Chinese characters and derivatives (collectively, CJK characters) in their writing systems. As of Unicode 9.0, Unicode defines a total of 80,388 CJK Unified Ideographs. (see https://en.wikipedia.org/wiki/CJK_Unified_Ideographs for more information).
I must confess I view the prospect of having to learn 2,000 emoji with very little enthusiasm. :(