Man, these snake oil salesmen cheese me off. Bobby Jones said that anyone who was dumb enough to believe he could go out every day and play golf as he pleases is a greater fool than ought to be left at large. Golf just isn't that sort of game. And, if it was, it would not be nearly as enthralling. Let's face it; golf is like a box of chocolates. You never can be certain how things will go every time you tee it up. It is not subject to being mastered the way snooker or chess can be. There will always be the element of luck involved, even if you are able to find a consistent swing.
What separates the champion from the also-rans is what is between their ears; the ability to size up every situation and pick the right shot; the ability to concentrate and try your hardest on every shot, not just the difficult ones; and the determination never to quit.
Walter Hagen was a great player and very much played to the gallery. He was said to act as though the hard shots were easy and the easy shots were difficult. In some respects, he had the right idea when doing so, because by not over-thinking the tough shots he probably avoided becoming too tense, and by working hard on the simple-looking shots, he probably ensured that he did not experience a let-down by being too casual about the shot.
Concentrating, and giving every shot your full attention, is required to play your best golf. However, it's easier said than done. There are very few golfers who are able to do it. As for the notion that you can have your A-game every day; you need to, as my wife likes to say, "nip that in the butt."