That's a good point. I'm a big reader - and I have lists of thousands of books I want to read. But one reason I semi-on-purpose still pick up random books that I stumble across and look fun, even if they're less "optimally chosen" by me, is exactly so that I sometimes stumble on things I would otherwise miss.
Or maybe just, like many readers, I love buying new books almost as much as reading them, and this is just an excuse to buy more... :)
For many things in life I try to find and loosely follow some ideal ratio of explore vs. exploit. For restaurants I've found 1:3 ratio works well - 3 times eating at restaurants I know I love, then the fourth time eating somewhere I haven't been yet. Usually the new restaurant doesn't live up to my favorites, but sometimes I find a new favorite.
That last bit resonates with me so much! In fact, there’s a word in Japanese for it - ‘tsundoku’! Ever since I stumbled upon it, I feel almost vindicated :)).
Or maybe just, like many readers, I love buying new books almost as much as reading them, and this is just an excuse to buy more... :)