A naïvely constructed die - i.e. a perfect cube, but with pips dug out for each face - will already bias in favor of 6 rolls and away from 1 rolls simply because six pips require removing more material (and therefore mass) than one pip. Likewise with 5/2 and 4/3. The "precision" dice used in e.g. casinos address this by filling in the pips with material exactly as dense as the die's base material; the injection-molded dice in most board games (let alone wooden dice) obviously ain't constructed with that level of care.
This is also part of the reason why some dice games - particularly those typically played with cheap dice - deem 1 to be more valuable than 6 (example: Farkle) or require at least one 1 roll to win (example: 1-4-24). Or they'll require some number of high dice to make the game ever-so-slightly less brutal (example: Ship-Captain-Crew).