From my perspective, it's more that he used to be competent, but something has changed over the last 5-10 years, and now he's essentially coasting (or more nefarious things) off the massive amount of wealth he's piled up. If you or I could come up with many better ways to accomplish Musk's stated goals than he seems to be able to execute, why would I not conclude that something has changed and he's no longer as competent as he once was?

Or maybe I'm just blinded by partisan hatred. Who knows, but I'm still not interested in supporting anything Musk produces these days. I guess we'll see in another few decades whether I'm seeing it correctly.