I think the thing about the friend zone is once you admit you like the girl, any interest she had in you is gone. I had a friend who wanted to be in a relationship with me, but I didn't find her physically attractive, and her home life was a little too dramatic for me. We were good friends and I got away with tons of sex jokes around her openly displaying desire for her, as I did have some interest, and she changed up her look and what I was looking for changed. However, once I openly admitted I wanted to be in a relationship with her, she declined. She "didn't want to ruin the friendship" but at that point it was already too late. You don't slowdance with your friends in your back yard.
I don't think it's guys making the excuse, it's girls who don't want to hurt the feelings of guys. I'm not one to admit that men are more sexually uncontrollable than women, but truth be told if just about any female friend I had wanted either a relationship or something physical, I wouldn't say no. I have a female friend who I wanted to nail from the first time I saw her. Her statement was that "I wasn't her type" because I am more of a pretty boy/rocker and she is a scene kid. True or not, she's like a big sister to me now. She has a boyfriend and it doesn't bother me because he treats her like gold. At this point I'm not sure if I would have a one night stand with her, she'd have to at least be single. However I would love to have a relationship with her. O well, it's nice having her in the big sister role, and it's been more amazing knowing her than any girl I've dated. Not that the feeling is mutual.
In the end, I'm just a good looking guy in great shape who loves life and would treat any girl he dates like gold and would never think of cheating on her, and also has a car and apartment, and at the end of the day I'm still wildly lonely to the point of depression because I can't get past the friend zone. I guess girls just like guys that fuck them, treat them like shit, get them pregant, and leave.