I think that one boils to basically back in 1990, ISO 10646 wanted 32-bit characters but had no software folks on that committee, while the Unicode people was b

I think that one boils to basically back in 1990, ISO 10646 wanted 32-bit characters but had no software folks on that committee, while the Unicode people was basically software folks but thought that 16-bit was enough (this dates back to the original Unicode proposal from 1988). UTF-8 was only created in 1992, after the software folks rejected the original DIS 10646 in mid-1991.