That's all nonsense about run in. There is not a lot of difference between fully synthetic and high grade dinosaur oils as far as lubrication is concerned.
Some new bikes are coming with full synthetic fill from the factories.
Some synthetics are super refined dinosaur oils. Shell Rotella T6 synthetic is 100% dino, Mobil 4T has dino oil and synthetic in it. Big lawsuit between Castrol and Mobil years ago. Turned out group 3 oils which are super refined dinosaur oils, are classed as synthetic.