And that's a good thing. UB is another mechanism to speed up the development of compilers, many other languages fall trap to over defining while we lack the methods to solve such problems cleanly (believe me, the modern c++ people have tried). Usually this is the case because they believe strongly that their methods work despite evidence.

As for UB, the compiler has the final say. Nobody should write nontrivial c without understanding their compiler, the same as nobody should write c without understanding their text editor.

Code in other languages breaks between versions, in c there are projects with code from every version at once!

Looking at it another way, work put into a c compiler enables you to write nontrivial code.