Over the last few years BMW strategically chose to shift investment away from their current line-up into their electric line (and I think Germany's and Europe's charging infrastructure, which they have a standard for and are backing). They had nothing to show against MB's 2016 generation and haven't had a good year for car sales in comparison. Now that MB has got that '16 release out of the way looks like they're going 100% into competing with and catching up to BMW's electric line up. BMW already has the super-hyped up i8 and the i3 (and depending on your taste they may the most beautiful or the most ugly cars ever designed). MB just discontinued their only electric. BMW should have one more ICE refresh 2018-2020 and then it will be electric/hybrid all the way.

they are probably concerned too about tesla but at the moment bmw, mb and vw's audi are probably the three auto marques who can each crank out a couple million electric cars a year by 2020 if they wanted to. it's that volume that makes them competitive.