Can someone explain why the ROTC cadets on the field with the President before the Anthem at the Nat Champ game are not wearing any ribbons?

ROTC cadets aren't authorized to wear any "real ribbons" unless they earned them as prior enlisted before becoming a cadet. They probably could have worn their ROTC ribbons, but I think they made a solid choice not wearing them since they are made up anyways.

It is very likely that they may be ROTC cadets THAT HAVE NOT signed a real military contract yet. A student in Army ROTC can be a cadet for two years and are not REQUIRED to sign a contract until their Jr year. I dont think ROTC awards cadets with real army ribbons until they receive their commission or sign the contract. Interesting enough, though, I see some GAFPB's and an Air Assault badge. It's odd that they can get opportunities to earn these badges before they are even authorized to wear an ASR or NDSR...

Interesting post, I've never seen a uniform like this!

That's certainly interesting since 2 of them have the GAFPB