That is a pretty dire. Lol I don't agree with that.
But what I am interested in is exactly what your theory is? I was under the impression that changing oil too frequently is detrimental in the sense of the oil doesn't have long enough to break in and bind to compenents to provide protection. The point the guy made was, by the time the oil actually starts working properly then you change it out and then its pointless. It was over on the u.s side of the forum. He ran tests and had conclusive evidence that the oil changes in between were pointless.
But then again its difficult to put into a template for everyone. I may triple your miles. You may do triple mine. So in 6k someone could have lasted only 2 months or a whole year.
I had the 330i e90 for 4 years. And change oil in between services and change plugs even at oil service. But my was driven hard and used a performance car as u put it rather than a town cruiser. It ran like smooth as butter.
Would it have ran as smooth if I stuck to manufacturer schedule? Probably. But bmw messed up with run flats and cracking alloys. Hydro bushes and one thefts. So why should I trust anything they say?
The point is they have schedules for everyone. That's the guy who tracks the car and they guy who got a car from work as a repmobile. My car is not driven like his. Nor should I service it like him.
Your comment about using cheaper oil for frequently is also ridiculous. In which case then do not buy premium tyres just budgets. And enjoy.
I think I will continue to in between oil changes and premium tyres mate.