[JdeBP]

That is a bit misleading to the point of error, on several points:

* Your timeline is backwards. UTF-8 was designed for a 31-bit code space. Far from that being its future, that is its past. In the 21st century it was explicitly reduced from 31-bit capable to 21 bits.

* UTF-16 is just as standard as UTF-8 is, it being standardized by the same people in the same places.

* 17 planes is 21 bits; it is 16 planes that is 20 bits.