Can a product be considered a failure if it was never made available for sale to the public? This is exactly why Apple is secretive about its projects. Sure, there have been true failures like the iPod Hi-Fi, the eMate, the 20th Anniversary Mac etc. But to consider the car project to be a failure is presumptuous and premature.
We do not know if they have these projects because there is no definitive information about them. Even the people who do know may choose to sandbag and outright lie about it. And that's my point; it's ridiculous to judge whether something is a failure when the market has not had a chance to decide if it was a failure or not. At the end of the day, that's the only thing that matters.