The big difference is Tiger can do that with the face of the club, and can choose the times when he does it :)

Tour players have very different lofts depending on type of iron and ball flight. For normal players though, companies like to deloft the irons to 1) make them go further so if you're comparing a 7 iron, you want to buy the one that goes further even if you don't know the reason is because the loft is different and 2) because the cavity backed design and soft material makes the ball fly higher than a blade, which can cause problems. Like the wedge example, a soft cavity back can go super high so they have to knock it down a few degrees.

Unfortunately, not any more. :(