I knew a family in LaCrosse, Wisconsin back in the middle 1990's that did exactly this on Mobil 1 -50K and not change the oil at all? ...... In fact, without bypass filtration, there is no PCMO that is going to last 50K.
But why don't you test it and report back?
- every vehicle in the family went 50,000 miles per oil change, on Mobil 1 exclusively.
I should have asked how often the filer was changed - - but I was too much in shock (awestruck?) to think to ask.