[cuddlybacon]

I think the problem with long term goals is not that your preferences may change but you don't update your goals. I think the problem is procrastination.

Consider this variation of your Scenario A: You make explicit goals to read 3 relevant books, take a sailing class, and save $10,000 for a boat. You find yourself in mid October having only read 1 book and saved up $2000. You end up not sailing until year 4 even though year 2 was certainly achievable.

A better variation of Scenario A: Breaking the big goal into smaller ones can prevent this type of procrastination. Instead of save $10000 by end of year, make 26 goals to save $385 every payday. Then make a goal to sign up for the sailing classes by June. Then based on that June date, decide to read book 1 by Feb 28, book two by April 30, and book 3 by June 30.

In the second variation, I assert you'd be much less likely to procrastinate to the point that your year end goal becomes unachievable.

Perhaps you assumed in Scenarios A and C would do that. Your post would make more sense that way. But I find most people do not do any breakdown. They'd just set the end of year results as the goal the reach a point where they realize it is impossible to achieve any of it.