Yeah I'd call that a bit of a conflict of interest. VW wasn't doing what they were doing to increase efficiency (not primarily anyway). They were keeping NOx emissions down, which can be dealt with, just not at the price that VW wants to sell cars. I imagine most of the discrepancy is due to the fact that people drive like assholes most of the time. The way we accelerate and break can easily bump the fuel efficiency down a lot. Maybe not 50%, but easily 20, 30%.

Anyway, there's no way that electric cars will ever be more efficient than gas/diesel cars. Electric cars require a minimum of three energy conversions, so even if there are zero emissions at the tail pipe, most of your dollar savings is due to coal being dirt cheap, not greater efficiency. Electric cars have the potential to be less emitting than IC engines should we all be using solar and wind eventually, but they won't be more efficient, because the physics don't really support that. Musk risks his own credibility when he says stupid shit like that, even though people want to fellate him even more every time he does. It's not a compelling argument, because it's not true (which I take as a standard of compelling).

We could all drive Corollas and we've hit our fuel efficiency standard overnight. But so long as people want 5-Series and Model S we're not anywhere close to reaching the limit of fuel efficiency.