Steve,
Modern motor oils are crammed with additives. This is what makes them able to perform the tasks we ask them to. Without VI improver's, detergents and dispersant's, ash less compounds and whole lot more, our modern day engines wouldn't last 5 minutes.
There are enough goodies in most automotive lubricants to allow them to work hard and long. Many companies have convinced John Q Public that they need more goodies, or that more is better.
Some after market snake oils work and others merely inflate the manufactures bank account. About the only was to avoid being zoomed is to study up on what you're intending to buy.
That's my take on the snake oil snafu!
Stuart
