I have to admit, as a younger man I used gunk motor flush at every other oil change on 3k mi. interval on Pennzoil 10w30 conventional, for over 100,000 miles on a '99 Dodge Stratus. Never had a lubrication issue, ever. Never consumed any oil either. I'm just saying. Car ran well the entire time I owned it. It was my first car... Good times.
Now, that was pre-BITOG of course, but I'm still not against running one say on a 20-30k basis in a high mileage daily driver.