Gee - it's almost like no one wants a truck that doesn't truck, and a car that you can't even wash without damaging the surface of the world's most stupid material. But the Cybertruck did achieve ONE very important thing: It taught people that stainless steel is not stainfree steel.
Theory: The Cybertruck was Musk's "I'm bored with Tesla" project, so let's create something wild. All that effort that could have gone into creating a lower cost Tesla was instead spent creating something for an audience of just Elon.