That simply isn't true. The contaminants are captured in the filter and stay there unless the filter fails. I myself use $12 K&N oil filters and generally change them on every second oil change. The oil doesn't look dark even after 5,000 miles. The cheap filters I wouldn't trust for even one oil change; the chance of an internal tear is too high.
It’s like keeping 1/4 of last night’s dishwater to wash tonight’s dishes.
That's a false analogy because the contaminants don't circulate through the system. I periodically send an oil sample to an analysis service and it always looks good.
Of course, you must be correct. I have a mere 30 years as a mechanic and engineer.
The acids and other soluble contaminants do NOT stay in the filter, but continue circulating.