Elon himself gave an explanation to why Fisker failed:

"Fisker thinks the most important thing in the world is design, so he outsourced the engineering and manufacturing. But the fact is that's the crux of the problem. And he's outsourcing to people who don't know how to solve the problem. So he came up with a product – it's a mediocre product at a high price. It looks good. Particularly from the side it looks good. I don't love the front. It looks too much like a caricature of a Mexican Bandito, the grille. The car looks very big, it's bigger than the Model S, but it has no trunk space and it's cramped inside, particularly in the rear seats. The mark of a good design is something that has great aesthetics and great functionality."