OK, you made some "assumptions" about comments that after reading multiple times, I do not see anyone made. NO ONE stated every factory rifle was an MOA shooter, and that is no different than today. HOWEVER, many rifles from decades ago were capable of far better performance than MOST shooters were capable of shooting. No different than today.
I have purchased my fair share of used rifles that people thought were junk, because they could not get them to group well with their choice of factory ammo. After proper cleaning, handloading and maybe a trigger tweek or so, they were fine to sometimes excellent shooters. Like any sport, there are those who perform at different levels.
We all agree some of the modern tech has improved the shooting sport, and it was people like many of us who drove and drive those "improvements". As an old bullet swager and high level comp shooter, I understand this all too well. However, things were not nearly as bad decades ago as some people today think they were. Even with the many advances in tech, several of the old shooting records from decades ago still stand today.