When you think what Elvis did for music, and when he did this, music was not as accessible then, as it is now. Lots of folks didn't even own a record player, if it was back then for this Glee, what would have happened, I don't think this is significant as what Elvis did or is doing after all the years he has been gone. Plus this is a group, Elvis was a single performer.
If this was today, Elvis' record would soar above any and all entertainers in the music world.
Elvis is still the greatest entertainer that ever lived.