At that point, yes, you could abandon formal goal setting and still do things mostly correctly. But it's terrible advice for most people.
Then some of it is wrong:
> The idea of having concrete, achievable goals seem to be deeply ingrained in our culture.
Something silly like 90% of people don't have concrete, achievable goals. If you don't, I'd strongly encourage you to start thinking about what you want, and writing it down, and occasionally revisiting/rewriting what you want. It'll do wonders for you.
Yes, you won't follow the plan to the letter, but you will live a more meaningful life and get more of what you want.
Eisenhower quote: "Plans are useless, but planning is invaluable."