Bypass filters are not merely an afterthought nor are they obsolete. In the over 45 years I have owned Cummins Engines, they have had both full flow and bypass filters. In 1986 Cummins combined a full flow and a bypass into one can.


http://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/LT15034.pdf

I have been using the LF3000 Since its inception in 1986. My smaller 10.8 Liter engines also use a combination full flow , bypass filter.

http://www.cumminsfiltration.com/pdfs/product_lit/americas_brochures/PD10010.pdf

It is still OEM on current production engines.