Those are made up of much smaller chiplets. No individual die is all that big

Oh the reason they don’t make dies that big is the probably of a defect balloons and your yields would be shit.

Apple handles that in part by fusing off the broken subcomponents of the huge die, though, which is how they end up with stuff like a 7-core GPU.

Every chip manufacturer does that, that's how they come up with cheap, low end parts. They just try to keep number of cores an even number, so the trick is less obvious.