Note for example that many books are poorly written

True. That means you just have to take the right book.

and some subjects don't have good books.

Not really the fault of books now.

Moreover, different people prefer absorbing information in different fashions.

Acceptable thing to say but an rather vague one as "preference" can easily be like that stupid "i has add lol cant read" (an rather extreme one, but humans are not automatically strategic and all that I guess), but admitting that good books has and always been a standard for a wealth of great information is not an understatement.

Most of this is less about books but rather about the information (utility). The only thing that matters is that they get the best bang for their buck. And for that.. books. Correlation, casuation.. eh.. let's keep it simple.