I'd wager the mass production of the items probably lent little time/desire to 'fiddle around with the machinery' and specifically tweak the patterns
Where the neat patterns/value came into play, would be on the schoolyard, or trading marbles. Back in my day (geez I'm starting to sound like and old man) a cool pattern/color was more desirable than a plain(er) type even from the same manufacturer. Hence, some of the nice pattern ones were damaged because they saw a lot of action as some kids favorite. But I'd estimate 1/100 or even 1/1000 from some manufacturers really stood out compared to their more generic counterparts.