An "ideal" being is many layers of "better" than you are, whereas something that is simply better is only one layer better. To get to ideal, you would have to imagine someone better, then imagine what that person would consider better, and so forth, until you hit a state where there are no further improvements to be made.

In my understanding of academia, people can be very resistant to integrating ideas from "unrelated" fields. The statistical tools that any one person uses are probably more determined by the status quo than anything else. I vote for options (2) and (4) as the most likely.

This is a really good point.

It is easier to determine whether you are doing "better" than your current self than it is to determine how well you line up with a perceived ideal being. So perhaps the lesson to take away is to try to just be better rather than be perfect.

Writing is not very effective? Perhaps you meant "not very efficient"? The right thoughts at the right time given to the right person have had extremely profound effects throughout history (e.g. Karl Marx. Notice I said "profound", not necessarily "good") However, the percentage of reading that results in profound effects is very small.

I think it would be very interesting to compose a reading list, or a reading decision tree, that is as short as possible while communicating the most important possible ideas to someone, especially a young person.