Mobil-1 is not one of the better oils, despite what one might think. There are many varieties of it. The truly superior Mobile -1 is the high saps euro version. (Made for Porsches, BMW's, and Audi's).
Up until recently the versions sold in auto parts chains were of the cracked mineral oil crap culprits. In my VT days several guys on my forum burned up turbos on that junk. ( And it was some Hyundai dealers that were using it on these failure cars).
Current oil in general doesn't do non ferrous bearings any favors. Retail oils are made to manufacturer specs, and then political requirements. (Which definitely don't do cars any favors). All of the new specs that oils like Penzoil Platnium and such were an industry response to severe restrictions imposed on them by 8 years of the Obama administration/EPA.
In those years all the add packs and chems that the industry used with good effect were outlawed. A perfect example of this was the old vaunted Royal Purple, which turned to crap overnight. They could find no replacement for their now illegal additives.
Trends in engineering smaller oil guides require extremely light oils that really can't provide the protection that heavier viscosity oils once did.. But God help you if you think you are going to just put in a heavier oil. Say problems !
Lots of cold start wear, short trips where the oil doesnt get nice and hot are the leading cause/majority of wear in any engine. So driving habits can play a part in excessive wear on bearings. Hotter climates, longer trips produce less wear over time on bearings.
**It is not a common issue for these 3.8's. There's plenty of dudes on here with serious mileage on their BK2 3.8's and they say nothing about excessive oil consumption.
****You are right about the once it starts,...it surely doesn't get better
