Some monitor manufacturers performs a rough calibration before they ship out the monitors.
But lots of things to consider about it.
1) The calibration changes with temperature.
2) The calibration changes with age.
3) The calibration changes if any control setting is changed.
4) The calibration changes if the computer runs with a different profile than the reference system.
5) The surrounding light matters.
6) ...
In short - the sales of hardware calibrators doesn't just happen to get a few companies to make extra money.
