This oil is probably only 3 to 5 years old, but seems to be working fine. Some guy posted a used oil analysis a while back for a GM car that had been sitting since like the '80s. And the oil was still in pretty decent shape. Oil just sitting in a bottle or oil pan seems to be all right.
You're probably right, but this is 2-stroke oil, NOT 4-stroke motor oil. Different thing.
This means its intended for use in a total loss system.
This in turn means that, unlike 4-stroke motor oil, it doesn't need
to have high oxidative and thermal stability, so perhaps it doesn't.
This point comes up sometimes re using 2-stroke as motor oil (which I have considered as a work-around to try and get a smoker through a UK MOT test, reasoning it would burn cleaner).
General drift of informed advice there seems to be:- DONT