Interesting and amusing, but it's also "back in the good old days when I was a lad" nonsense.
The author is at once saying this Fields bloke reckons nothing's changed if there are guys trying to get away with easy sessions and also saying it's all different these days because guys are doing easy sessions...... pick one!
And as always, it's an appeal to authority. Does this Fields guy training so hard and being a great cyclist mean its the best way to train? Not necessarily. It's an anecdote and not a whole lot more.
Having said that, I don't think cycling is equivalent to running in terms of ideal training intensity. I'm no authority on the subject but you can train harder without inflicting the same need to recover as would be the case with equivalent running. The impact forces from running surely make it much more demanding and necessitate longer recoveries from high intensity sessions. If your volume is relatively low, it's very realistic to do quite a lot of training around threshold or VO2max intensity and fit in some lower intensity stuff when you have time. That approach is not so wise with running...