Dehyrdration of the meat. The protien fibers are missing a lot of water after sitting in a bag that allows the moisture to escape. This causes less steam to hammer the protien strand when it hits the grill. That causes a maillard reaction deeper then a non-dehydrate piece of beef. Which does make the steak taste different.
Several things you will also find when guinnesses like Alton Brown push home dry aging. FIrst, it shows they no nothing about dry aging.
Second they always chose prime rib this is because it is impossible to screw up a piece of prime rib, it is by nature a perfect cut of beef. So they use it because it is going to taste way different then the strip and chuck steak most people can afford.
Third, they cut off the fat. This is against dry aging. You need an excellent fat cap to dry age because the fat is the protection from molds and unwanted bacteria.
Why do they cut the fat off a perfect piece of beef?
Because fat holds in the moisture. They always say safety... also proving they no nothing about meat. Fat is a preservative. It is removed because it slows the dehydration process. And they need a dried out piece of beef. The only thing that saves them is they always use a rib eye. Which can take a lot of stupid things done to it and it will still taste better than the normal steak most people eat.
They also play on the human psychology, I did this, I cannot wait to taste it, it is going to be so good. And everyone agrees. Cause they put the effort into it and have been told it will be better. Combine that with using a rib eye which most people don't normally eat and you have set the stage for agreement.
The real dry aging process (as in USDA approved or home butcher completed) is an enzymatic and Bac-T process that is breaking the protiens down to amino-acids, which are reacted on to create sugars. Dehydration is also part of the real dry age process, but the creation of the sugars is what it is really about.