What I recall was that he said the enhancements were an effort to help keep the meat juicy, even if it was overcooked. The idea was to make a product that was appealing to the general public (i.e. it wasn't dry). He specifically stated that some people still think pork needs to be cooked well past 160ºF because that's what Grandma told them. The enhancement is kind of like an insurance policy to try and help keep the meat moist. I think he also stated that the enhancements were also to add shelf life to the product.
Marination (as he called it) was to help tenderize or break down the meat and add flavor, but not necessarily to help retain moisture.
The presenter did say that the amount of enhancement solution was self-limiting which means that at some point, too much solution effects the flavor in a negative way. Therefore, there is a practical limit as to how much enhancement can be used.
I'm not a meat scientist, but I did stay at a holiday inn express once. :-D
