Some Jewish scholars have fatal “Spectatoritis” – they don’t do any real work (neither for nor against; neither with nor without profit), so they don’t know anything beyond the activity of book reading (ergonomics?). Nor do they recognize their knowledge might be lacking.
We learn not only from reading, but also from doing. And when your books are wrong, they must be corrected by experience. Hyehudi has already mentioned this idea, but it bears repeating.