It's not Patti in the video, it's a model named Dana Patrick. I think the Ellen/Karla case is a bit different, since Karla had replaced Ellen as a member of the band. Those old videos looked like live performances, so they feature band members. The
Anything video tells a movie like story and is designed for making a great visual impact. Have a look at Bonnie Tyler's
Loving You's A Dirty Job video, for instance: Todd Rundgren sings on the record but you see another guy in the video. Many Meat Loaf videos involve a lot of professional acting and create certain images, so the person who sings a particular part on the record might not exactly fit the character that is supposed to be represented in the video. Don't expect music videos to be authentic.