BMW was a leader in diesel engines since 1998, when the M57 was introduced. MB had very good engines, but BMW really made a huge leap over all Euro manufacturers with their Common Rail generation that started in 1998. Part of the reason why VW decided to cheat is that CR, introduced by FIAT and BMW around the same time, worked so well that they had to switch from PD to CR, and they were behind.BMW has always been better at engineering and manufacturing gasoline rather than Diesel engines. Traditionally, Daimler-Benz has been better at Diesel engines. At least, that's my opinion.
Please explain what's "obvious".
All that fell thru in 2015 when VW screwed things up.