The real truth is Syn oils tend to deal with heat and breakdown better than any of the other natural oil. Heat is how it is distilled to start with.
The real trouble today is that many of the additives have changed and the Syn oil has made up for their loss in some aspects and or to prevent damage to things like Converters and O2 sensors too.
With Zink being removed it has brought a lot of change to engines. It is one major reason every thing is roller now vs flat tappet. Yes less friction but also no wear or break in issues. Zink was killing O2 sensors.
Add to it the Turbo engines. Most would not survive on Dino oil. The carbon build up is much greater today and it kills the oil line to the bearing if it cokes up.
Same on many Direct Injection engines today. Engine all leak a little oil down the valve guide to lube it. Today no fuel is cleaning the valve and it can also coke up with carbon. The syn oils are more resistant to that and help prevent it.
Low tension rings today also can carbon up and Syn prevents this.
Oils need to be looked at like a socket set. No one single socket fills all needs but the same for oils as some applications need specific oil for a reason. Most modern cars are designed for Syn oils today. Most older cars can still use it some may not like it. Just depends on the build and needs.
Because of this that is why we have so many different opinions and ideas. While some people may be off base others are just in a different place with different needs as there is much variation out there.
All my vehicles and even my Generator are on Mobil One. I have used it for years with great results. They even have a high content oil for my one Flat Tappet car.
Now if I an old classic that ran with a Castor based oil that would require a much different fluid and that is fine. Not everyone can get by on just one type.
So stop arguing read up and learn what the oils are and best match your needs. Also keep up with the changes as some of the older oils are no longer around and you need to upgrade to a modern version.
Lord knows how many customers I have had put in new cams wipe a lifter or two out and not understand the loss of some of the phosphate's and Zink that protected their cam in break in and performance.