The thing I don't understand is how can they say facebook ads don't work and even be sure of this, given that, as others have pointed out, they aren't going for a "conversion" as the purpose of the ads is branding, so that people think of their brand and eventually may buy a car made by them. They do other forms of advertising for branding, including TV ads, radio, billboards, etc so I don't know how its possible to pinpoint one channel of advertising (facebook) and say its not helping them with branding.
My guess is that they have an expectation of having more user feedback and involvement from this form of branding (people clicking the ad, filling out some bullshit form so they can bombard them with marketing material, etc), however the nature of the product may preclude itself from this sort of consumer behavior because people don't buy cars very often they may not feel compelled to engage with the brand, however seeing the ads on facebook could potentially have the same "branding" effectiveness as TV ads yet they really have no way of measuring this.
My guess is that they have an expectation of having more user feedback and involvement from this form of branding (people clicking the ad, filling out some bullshit form so they can bombard them with marketing material, etc), however the nature of the product may preclude itself from this sort of consumer behavior because people don't buy cars very often they may not feel compelled to engage with the brand, however seeing the ads on facebook could potentially have the same "branding" effectiveness as TV ads yet they really have no way of measuring this.