CVO Don, what about the theory that since synthetic oil molecules are all the same size vs dino oil, that a less than perfect engine might burn/use oil because of this?
Another old wives' tale, right up there with "too slippery." My 45 years of chemical engineering + heavy industrial plant maintenance confirmed that those are myths. Oil usage is due to increased clearances between engine parts. If molecule size was a factor, then all molecules below the "critical size" would leak out, making natural oil more likely to leak.
Synthetic has several advantages, but its major advantage is that it is
far more pure than natural--so it doesn't have molecules that break down at lower temperatures (the primary reason synthetic is superior to natural in air-cooled engines), don't maintain the correct film thickness, or interfere with the additive package functions.
About the "too slippery" aspect: oil will naturally coat and cling to metal parts, but the contaminants in natural oil (that can't be removed by the distillation process, BTW) can decrease the oil's ability to cling, and also interfere with the additives that help maintain the oil film between moving parts. There has never been an engine, brand new or otherwise, using
correct type of synthetic, that has blown up or worn out sooner than it would with natural oil. Not trying to throw shade at anyone, but those problems with engines were due to incorrect assembly or bad parts or lack of assembly lube, etc, etc.---not b/c of synthetic oil.