The costs for cleaning up a Diesel can only rise with the more stringent emissions standards coming under greater scrutiny, although BMW has recently reiterated their dedication to the technology, especially in combination with bigger, upmarket vehicles.
Jeff Dahn, the renowned battery scientist working with Tesla, recently stated there were around 300 PhD's [!!!] working on improving LiIon battery tech at the Chinese ATL corp. alone. [ The source video is now private ]