For now.
"...modern gasoline direct-injection (GDI) engines in today's passenger cars can emit more hazardous fine particulate matter than a port fuel-injected engine (PFI), or even the latest heavy-duty diesels equipped with a particulate filter."
Attacking GDI engine particulate emissions - SAE International
GDI is nowhere near as clean as it is marketed to be (coincidence that tail-pipe testing became extinct around the time GDI ascended into our markets ?). Some (not all) GDI engines have horrendous oil consumption that is deemed normal, and is reflected in the Sx oil specs having to change here to protect the cats. Modern (and perhaps some older) TWO stroke gas engines don't use more oil than some of these GDIs. I'll be somewhat surprised if the engine oil that is
actually going through the exhaust system in some of these vehicles is accurately reflected in the "official" GDI testing.
Total cost of ownership is an interesting subject. Removing and decarbonizing
some GDI heads at less than 50k km in 2017 also reminds me of old 2 strokes...... :laughing:
As the SAE article linked above touches on, GDI is not done with additional hobbling and complexity....
Rgds, D.