One leather makes one book. Cows currently drop 0 (0???) to 2 leather. Either steve is a dumbass or these are the thickest books known to man because you can make at most two books from a single cow. With 3 needed for a bookshelf, you have to slaughter an insane number of cows to get just one decent bookshelf for decoration.
the solution seems pretty simple, too. Just make common mammal mobs (pigs, sheep, cows) always drop their particular hide which breaks down into 2-5 leather. Now two cows gets you a chestplate and some boots, or 3 bookshelves, or 10 item frames. These things have 0 reason to be rare and as-is it’s just a tedious grind for gear that is bottom-tier and blocks that are purely decoration.
and there’s precedent too. This would establish rabbit hide as the tiny hide, with pig being small, sheep being medium and cows being large.
hell, if they want to make villagers more important, make the leatherworker always start with a trade that just turns the hide into extra leather, so maybe the base breakdown for cow hide is 3 like sheep, but the leatherworker allows you to trade a limited number per day for 5