That's not what all girls want out of a relationship. If it was, girls would be perfectly happy being the spoiled children of their parents and have no yearning for a romantic relationship.
The girls in high school want to be treated like a princess, maybe, but nobody's the same the rest of their life as they are in high school. Unless they're total losers.
There's nothing you can do about your personality to make more girls like you, unless you want to live your life faking being someone else. Either they like you, or they don't. Being a super-nice dude isn't always part of that.
It's something you learn as you get older. Just because you act nice to everyone else doesn't mean everyone's gonna like you or even be nice to you back. You have to learn when you should let go and move on.
I don't think there was anything "wrong" with me either, or at least so specific that anyone could articulate it. I don't have much experience relationship-wise even though I'm married. My husband was only my second boyfriend, and the second guy to even agree for a second date with me. I wasn't going on a date every week, but I must have talked to hundreds of guys and
nothing would ever come of it. Isn't it supposed to be easier for girls to get guys?
The things that made me not hot to guys were things that I couldn't help. I'm underweight. I have no boobs. I hate dressing up. I have bug-like eyes and my nose is big. (I'm not ugly really, but I know I'm not a "hot" girl.) I have a stutter, in addition to a deep voice. I'm not social and I shy away from physical touch among friends. Plus, I'm very intelligent and my mom joked more than once that I scared guys away with that. Judging by how some guys treated me on first dates, I don't think that's too far from the truth.
I could have purposely changed some things about myself. I could try to make myself be a social butterfly, dress like a supermodel (because they're all skinny anyway), talk girly, and act dumb, and I'm not that kind of person. I would be miserable being that kind of person. The only thing to do then, was to keep looking. I would meet someone who accepted me the way I am, even encouraging it, and love for me for it. That's all I wanted in a relationship. My first bf thought I was "cute," and at least that was a
start.
I eventually did find him. It took 3 years of looking online, because clearly, being an introverted hermit meant I wasn't going to meet anyone in person who would check those boxes. He became my husband, because I know I should keep a good thing when I see it.

He
loves that I'm smart, and thinks I can do anything I put my mind to. He thinks I'm beautiful, even when I just roll out of bed. He loves that I'm an introvert, because he is too and we enjoy our quiet time together. He doesn't even mind my stutter. He actually hates girls with high voices who talk too much.
My point is, you're only 16 and you're stuck in high school, with no choice as to who's around you. It'll get easier in college, when you're around people who are at least choosing to be there to some degree, and depending on the size of the school, you'll have a larger selection pool. It may or may not get easier after college depending on your work hours, but there's always online dating, and being an adult means you get to completely choose who you spend your free time with. The only thing that can stop you is yourself.
Don't forget, you should have some standards too. Despite my sob story above, there are certain guys I would have said no to. I weeded out a lot of guys at the chat level because they sent me creepy vibes, and I didn't want to waste one minute trying to date a guy who creeped me out. Guys with absolutely no ambition don't turn me on.
With all of the things that my husband gives me, I give him a lot back too. I support him and his crazy ideas. (Well, to a point.

) I let him do whatever he wants, short of breaking the law or hurting people. I'm open-minded. I encourage him to do better.
We try to make each other better people. Even if you're not sure if a relationship will lead to marriage, life is too short to waste on someone who holds you back, emotionally or otherwise.
Chin up, young padawan. There is much to learn in life, and to have fun too.