It used to be every song had a video to go along with and the video was released around the same time as that song.  More recently videos are made once a song has become successfull or if the artist is more established in the biz.  Scotty McCreery obviously had a head start in the industry because of his 'American Idol' win but has also backed up that start with a hit song.  Check out the video for "I Love You This Big"