Zilog Z80 was orders of magnitude simpler, but its designers never did something so foolish.

At that time, many people still used assembly language and they would have never accepted to write arithmetic expressions in the contorted way forced by RISC-V.

Now compilers hide this aspect of RISC-V so most are not aware of this. Moreover, most people are still using programs compiled from C/C++ with unsafe compilation options, or even from Rust, where by default integer overflow is not checked in programs compiled for "release", so they do not see how much performance RISC-V loses when executing programs that are designed to produce correct results.