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.