During the young part of my life (mid '60's) the oil Sears sold was said to be recycled.
'Twas said certain nasties were driven from the oil during its first use and that cleansing and refreshment of additives was what you're buying anyway.
The age of the base oil wasn't an issue.
If they re-refine old oil into reusable lubricating oil, does that free up production of crude to make more of something else?
Or is each barrel already worked to its most profitable, and they'd just end up stacking lubricating oil as a byproduct?