There doesn't seem to be any doubt that oils have improved over the years. Now, I'd like to see a similar test using a modern full synthetic oil compared to the modern petroleum oil. It would be interesting to see if there are any significant differences.
There probably isn't much oil of that age left in existence today. That can wasn't even marked as a multigrade oil on the can, so it probably predates the 10W-30 and 5W-30 oils made later. Even a multigrade oil from the 70s and 80s should perform better than those old straight grade oils did so any multigrade oil would probably work for breakin as long as you ran it only a short time.
That can looks like some cans I've got laying around from the 70's. The bulk oil we used when I drove a truck were the same color green. I don't recall any multi-weights until the mid 70's. You can still get non-detergent oil. You have to hunt, but it's out there. It's used in air compressors and the like. Pretty good test though. Maybe not on a par with what the oil companies have, but still pretty good.
I did my first oil change on my first car, a 1960 Pontiac Bonneville, in the summer of 1971. Used Havoline 10W30...
The factory owner's manual for my 1964 GTO and my wife's '72 Camaro both list straight grade and multi viscosity oil options.
Back in 2010 I started working for an ACDelco warehouse distributor that handled a "house brand" oil by the name of Pronto. Pronto was packaged by the Amalie Oil Company. I learned that Amalie Oil introduced the first multi viscosity oil:
In 1953, Amalie was the first oil company to introduce a multi-grade motor oil: Imperial 10W30.
When I grew up on a farm in the 50s, my Dad had a 30 gallon drum of straight weight 30 oil that we used in the tractors and trucks. The only vehicle that got multigrade oil was the car. We had a 15 gallon drum of 5W-20 for it. The 30 weight oil barely poured out of the barrel when the temps in Winter dropped down to -30 or -40. The multigrade 5W-20 was much better in the cold.
This guy on project farm does all kinds of crazy tests with oil and everything else. He is very good at what he does. I like the lawnmower engine stuff. JB weld on a connecting rod even a head made from it.