Great article and a lot of it will ring true with many self-taught or self teaching players.
Here is my take on it, i find many of experienced players that come to me have all there information disorganised, they certainly know it but it is just everywhere in their minds, so they do not settle on, or find what the want immediately how they want to use it.
I liken it to a room with everything scattered about in it.....what you want is in there somewhere....but where.
So what we do is tidy up that room, get everything in boxes so to speak, where we can draw on it, and order those boxes for use.
Practice time is about practicing what you use the most within your playing situation, this may be difficult for some players, but a pro can certainly sort this out.
Certain skills are interchangeable and some are one skill that reveals others.
Such are scale running up and down over an octave, over the neck, over the scale types. The simple act of once a scale is learned, to play the lowest note available to the highest note available over the neck is a multiple lesson in one by limiting the player to use this one idea, rather than practice all the ideas separate.
If the scale is C major then the player will start on the open E as that is the lowest note available to them. They will play a natural A minor scale within this exercise, as well as triad, chord, chord extensions, many times in some cases,
If the player names the notes they play they learn the neck and where to find notes, they learn what notes are in CMaj 9 or Am7 (this leads them to work out and see C7 within the scale as they pass the b7 to reach the 7).
It paves the way for intervals, inversions, modes etc etc......all this from practicing and learning to play a scale over the whole neck, not over an octave. In order to do this all fingers get a work out, all fingers are used. Different options of notes to use means different paths to walk around the neck and so on.
So rather than going around this 'room' and just pick up stuff to do, organise it, put like minded ideas 'into boxes' and practice the whole box of ideas for a while, then try another box.....it will amaze those that have not done such a thing exactly how much they know....or do not, if that is the case then you now know what you should be practicing.
Great to see Jeff using more open teaching ideas, the one string lesson he would have dismissed many years ago as a gimmick.