Mercedes have produced a few concept EVs over the years, like their all-electric AMG, but nothing serious. They clearly viewed it as a far off technology, much like many of the people on Slashdot who still can't quite accept that it works and actually makes pretty much the best luxury performance sedan you can buy.
Well, as I've stated above, the problem is selling them. The kind of people who buy their cars aren't buying the arguments about electrics, it doesn't matter if they're right or wrong. They're the ones with the money.
If Mercedes became convinced tomorrow that they could sell more EVs than dino drinkers, that's the direction they'd head. If they can make balls-out concept EVs, then they can make an actual car.
I just (yesterday) found a module with a bright sticker that says PROTOTYPEN in the E-Box of my A8... egads!