the manufacture saw no sense in putting more holes in the boat than necessary.... when you cut a hole in the cockpit floor, it creates a place for water to drip in, or for water to get into the core.... basically its another place for failure to start with no reasonable gain by cutting it in...
but some boats do have holes in the cockpit floor.... for emergency tillers to insert into the rudder stem...
some have engineered hatches for access to the motor, and some boats have hatches/portholes installed in the wall/sides of the footwell.
its highly probable that there are other boats that have holes cut by its owner for whatever reason they want to cut a hole....
keep in mind that a hole over about 6" round will begin to weaken the floor/core structure, and the more you cut out, the more integrity you remove from it....