Once you become a captain at a major, there is not much else to do and advance.
If this is your core hangup, then you may be right that the industry isn't for you.
Here's what I will offer: what you want out of work and life in your 20s is probably not the same as what you will want in your 30s and definitely not the same as what you will want in your 40s.
I spent my 20s and 30s as a military officer and pilot -- a merit-based job where advancement in jobs and responsibility was really only limited by how much of your life you were willing to pour into it. I loved it as a guy in my 20s and early 30s and basically made my life
around that job. I delved deep into the job with everything I had, I made my way through the ranks, had many adventures, had responsibility and leadership...all the things I'd dreamed of in a career and more (good and bad, of course). It was terrific.
But by the time I turned 40, it was no longer my bag. Having spent a lot of time away from home (both deployed to other countries as well as time spent at work on any given day), I realized I was missing a lot of my life *outside* of work. I wasn't able to really spend important time with my family, and by now I had school-aged kids that I wanted to be more involved with. I had a couple hobbies I enjoyed that I'd also been unable to really get into because of the time I had to spend working and the locations the military made me live.
Transitioning into flying for the airlines was like a big ray of sunshine blazing into my life. Unlike being in the Air Force, where the job occupied most of my life and I had to fit fun and family into the narrow spaces it didn't occupy, the airline life has basically inverted those priorities. The job doesn't occupy a large footprint of my life, and allows me to prioritize where I want to live, when I want to work (and be off), and pay attention to my family and my hobbies.
The idea that, as an airline captain "there is not much else to do and advance" sounds like a panacea to me -- way more time and money to do the things I want to do on the side, rather than things to keep me wrapped up in work.
I remember being a 20-something hard-charging fighter pilot and thinking how lame life would be flying a big bus around and "hauling rubber dog**** out of Hong Kong". I never would have entertained the thought that one day I'd be doing exactly that and loving every minute of it.
So, when making a career decision like this, I'd urge you to not just think about what the job *cant* do for you, but what it *can* offer...and that is choices to do whatever you want, however much or little you want, and still make a very good living to support both your family and (possibly) your hobbies and interests out of an airliner cockpit.