I think long term projects typically correspond with appropriately larger challenges. That's why I used losing weight as an example.
Even with losing weight, it is much easier to understand what you are getting into when you want to drop 3kg vs 30kg.
In my case feeling cold all the time for about a year wasn't something I have predicted when I started it. Or how difficult it is going to be to manage clothing department. Or to learn new recipes.
Now, none of the above would cause the project to fail, but one quarter into that year I figured out I need to find ways to keep me focused on the goal or I am going to fail. Just eating less wasn't doing it for me and I felt constantly hungry and miserable and I would soon drop out.
So I had to pivot and be innovative to be able to finish the project.
But... that's just the thing. You had a goal, not a long-term plan.
With that you would have set yourself with activities that stretched the span of your endeavors, say for half a year each week I lose 1 kg. I do that by eating this, exercising like that, etc. Then, things start falling apart with the hurdles you mentioned, and you adjust your plan by changing recipes, trying to find more fitting clothing, etc. So, you adjusted your long term plan to still reach your goal.
The point this article is trying to make is that you shouldn't stick to your plan but rather keep in mind your goal and change the plan along the way.
It is just an example. Simplification is a useful didactic/communication tool.
Project I normally work on span tens to thousands of people but they are usually very complex to give as examples without spending some more time thinking how to best explain it.
Even with losing weight, it is much easier to understand what you are getting into when you want to drop 3kg vs 30kg.
In my case feeling cold all the time for about a year wasn't something I have predicted when I started it. Or how difficult it is going to be to manage clothing department. Or to learn new recipes.
Now, none of the above would cause the project to fail, but one quarter into that year I figured out I need to find ways to keep me focused on the goal or I am going to fail. Just eating less wasn't doing it for me and I felt constantly hungry and miserable and I would soon drop out.
So I had to pivot and be innovative to be able to finish the project.