If "Keep It Simple Stupid" causes one to make something complex, they have failed to keep it simple, and can't blame the principle for their failure to adhere to it.
Marcosdumay did not state that "complexity" was the problem, but "requirements evolution".
Following KISS and YAGNI means you hard code lots of assumptions. When the requirements change, it means you have to fix all those subtle hard-coded assumptions everywhere and that is usually hard.
Also, if a single concept pops up as something that's needed once every month for six months, it's way easier to have that get re-implemented six times rather than abstracted.
Following KISS and YAGNI means you hard code lots of assumptions. When the requirements change, it means you have to fix all those subtle hard-coded assumptions everywhere and that is usually hard.