I'm in general agreement with your post, but would add some things.
First, while most guys can have an orgasm from a blow job, not all bjs were created equally. Some are absolutely, fan-f**king-tastic, while others are pleasurable, but not all-that. Obviously there is an experience level for the giver. I've found that older women, and women who enjoy giving are much better at it. As I've gotten older, it is also easier for me to ask for the things that please me, creating a better expierence with my partner. My own knowlege of my body and my sexuality has increased my ability to experience pleasure.
That leads me to my second point. Young men tend to not be good at oral sex because of inexperience on both their part and their partner's part. Young women, even if they are okay with receving, are often uncomfortable asking for what they want. That's partly societal and partly youth. Some women like very direct clitoral contact, while others like you more around the area. Directness, speed, and style can all be different from woman to woman. Young women likely don't know what they really like, and are probably shy about directing their lover. Saying, 'do this' or 'dont do that' could be perceived as criticism, unromantic or even slutty, so young women stay quiet and accept poor or non-existant orgasms.
As a guy, you have to judge a woman's reactions to see what pleases her. Young men don't tend to have the patience to look for those reactions, substituting vigor for empathy, which may be a good way to get a guy off, but is rarely a way for a woman.
Thus, it always helps if your partner gives you some guidance. Since that is more rare with younger partners, the experience can often be lacking for both of you. I don't know how it is for young women, but men have quite a bit of performance pressure on them. While society says that women should be demure and virginal, it says that men should be experienced and good lovers. All of those Hollywood movies show the woman's passionate reaction to the good male lover, so if the woman doesn't enjoy the experience, it must be the guys fault; he sucks in bed, and not in a good way.
As a guy who has always been fascinated, turned on and enjoyed giving, it definitely took me time to learn how it all worked. I've often thought that it would have been great to have an older lover to teach me things, but like most of us, I fumbled my way through with equally inexperienced girls/women around my own age.