Not necessarily. Having an ego usually comes with being successful. But in order to be successful, you must be strong, assertive, confident, and go for what you want - without caring what others think, or how it affects them (within reason). You definitely have to put yourself first, over all others, set clear boundaries, and not tolerate any disrespect, allow people to walk over you, or share weaknesses, or you'll be "finishing last".
Having an ego is one of those by-products of being a jerk. But note that being a jerk doesn't mean an ******* or ****head - although many are.
I used to be a nice guy who had a huge ego, and was arrogant, conceited, ****y, etc, and still wasn't respected, got used, wasn't very successful, etc - because I put everyone first, had low confidence, allowed people to take advantage of me, didnt stand up for myself, had no self-esteem or self-respect, shared all weaknesses, flaws and failures, etc.
The ego came mostly from all the attention and admiration from women. But the "success" was based on initial appearance only, and having an ego didn't make me very appealing afterwards. I was simply viewed as weak, insecure, shy, passive, afraid, over tolerant, etc, and was egotistical, arrogant, ****y, conceited on top of it. Worst of both worlds.
I don't think having an ego really helps, anyway - it just makes annoying, sound full of yourself, and entices people to tear you down and nitpick your flaws at every opportunity.
It's all of those jerk-like traits that makes you successful and appealing, IME. Just having an ego for the **** of it, or because you have certain materialistic things, and are social and very attractive physically doesn't mean anything. That's all fly-by ****, and based on initial impression only. Once they get to know you, and find out you are a "nice guy", or whatever, you're still going to fail, and be disrespected, pushed around, not taken seriously, looked down upon, etc.
You'll still probably get laid, but again, that's because you are good looking and have nice things - not because you have an ego. Much like being an ******* doesn't get you laid, but how you look, your behaviors, and what you say.
I think having an ego and/or being an ******* hurts more than anything. It certainly doesn't make you any more appealing, and even less so in the long run.
Even looking back in certain situations, I probably ****ed up a few hundred chances by going the egotistical ******* route. But that was based largely on insecurity, hate, self-sabotage, and going to the opposite extreme of the nice guy.
People can generally see through all this ****, which just makes them respect you less. Like, being a loud-mouth AW-braggart. Everyone knows its just an act, and a result of insecurity. Hence why none of those skanky-looking, shallow, promiscuous, *****s are taken seriously. They're insecure, have no self esteem, a strong desire to be liked, always seeking approval, etc. People know this, and treat them accordingly: like ****.
