I think this is about the medium shaping the message.
Each time a new medium arrives, it has an impact.
For many years, word of mouth, TV, books and magazines (and lessons) were the primary method for the delivery of golf info to most golfers.
So, for example, in the 1950s, the arrival of prosperity and TV allows thousands of people to see Ben Hogan for the first time. This is good and people are greatly afected by him.
But TV also creates many illusions in the minds of the viewers. The era of 2D instruction.
(Another effect of Hogan and televised golf 'arriving' in the popular consciousness at the same time is TV's role in creating his 'myth'. The other factor is the shift from matchplay to strokeplay - Hogan arguably developed the first great swing designed not to have things go wrong, rather than have them go right - or 'tournament golf' as he called it in Five Lessons).
In the magazines, we then went through a long period where instructors said stuff like:
'99% of you golfers don't don't turn your body enough' (not true in my case!)
The type of thing you have to say if you are trying to communicate via a mass medium. You have to treat every information recipient as though they are the same.
Some, like Jacobs, saw that not all golfers were the same and resisted the tempation to create a system.
But David Leadbetter inflicted his preferences (early wrist set etc) on everyone.
The internet is changing things again.