You don’t need self improvement mumbo jumbo.

You also don’t need a shovel to dig a hole when your hands will do just fine.

Digging faster with your hands can happen for numerous reasons:

If you were born with big hands
If you work out, you’ll scoop out dirt faster
If you’re a good planner, you’d dig near the coast in sandy soil
If you were born lucky, you hit a tunnel that had already been dug
If you were born smart, you might come up with better scooping techniques

So you conclude that your success of digging a hole was some mix of:
Nature – Being a strong, big handed man
Nurture – Working out, planning to dig in sandy soils
Luck – Hitting open cavities in the earth

And conclude that other people may need that self-improvement crap, but you don’t.

Indeed…it’s true.

People get rich without considering mindset (but ever known someone rich and miserable?).
Some don’t need to consider mindset / visualization if luck slants heavily in their favor like for a lottery winner.
When you see the rich & famous people and they never read Think and Grow Rich nor go to every Tony Robbins seminar, it’s not because that stuff doesn’t work. It’s because they simply didn’t need it anymore than they need a bobcat to dig a hole when they can dig with their hands.

I’ll take the bobcat.