I don't think there can really even be much debate that optics are better. A quality optic will get most people on target faster and with more precision than irons--whether it is an Aimpoint or EOTech for home defense distances, an ACOG for all around use, or a larger magnification optic for longer distance work.
However, I feel like irons are still under rated and under appreciated. A decent rifleman with good irons is still a very capable force. I consider profeciency with irons to be one of the very basic fundementals of riflemanship. That means that if you identify yourself as a rifleman, it is a crucial skill you need to develop and maintain. Besides, even quality optics can still break. I find that it takes me a long time to save up for quality optics once I finally save enough for a quality rifle. I take that time to make sure I know how to adjust the irons, and how to hit with them. I've taken my M1A out to 600 yards on paper with iron sights, and 1000 yards on more area targets--in this case a car sized dirt patch with a rock about the size of a car door in the middle. I find it to be both fun and challenging to constantly test the limit of my capabilities. When the rifle is like the M1A, providing both obvious power, range, and accuracy as well as a good trigger and excellent iron sights, and has the potential to reach out there a ways with you, it's even better.
But yes, I believe people need to know how to use irons, but when given a choice, I will always opt for an appropriate high quality optic.