It may just be nostalgia, but I think I was happiest when I was in college and the first few years of being in the Army. I think it was primarily because I had friends, a shared common experience with those friends, and the future was wide open. The world was my oyster. I didn't have much money, I wasn't married, no kids...so freedom was high but money was low. Couldn't wait to have some money though...
As the fortune cookie says, "sometimes money costs too much"...
As I grew in my career, increased my responsibilities, I got my money. I also got married, had kids, bought a house, grew my nest egg, etc... my security grew (money saved, stable marriage, nice town, etc...) but my freedom of choice diminished and my options narrowed. The world is no longer my oyster...I made important choices and now I have to live with them. I no longer had the large pool of friends/colleagues sharing a common experience. I just have my wife, my kids, my family members. I love my family. But we all know it's not the same. My options have narrowed, so even though financially I could technically do pretty much anything I ever wanted to do when I was young and free, I can't (or choose not to) because of my responsibilities.
Anyone else feel this way?
Not exactly.
Reading between the lines, you were happiest with vast choices and the feeling - perhaps excitement - that they brought. I didn't undertake the same responsibilities, so I didn't have a decline in choices the same way. I did experience a decline in choices over time because life inevitably means choosing something, but I don't feel the loss of the others as a bad thing. I don't argue with the inevitable.
It would be easier for me to feel bad about my failures to choose something exciting, or to maximize my skills/resources/intensity/adventures. That may be similar. But I kind of feel like "That's on me". Meanwhile I've begun finding new options, recognizing advantages in my choices, and so on.
I think nearly everyone whose childhood wasn't damaged felt very happy at some youthful point, and most people decline in happiness over time for a while. Some of that's probably responsibilities or lost choices. Studies show that after 40something, most people get happier again. That's been my experience so far.
I think that in the later ages, you become more at peace with yourself, your choices, and savoring what's available in the time left. Also you get through some of the burdens - children grow and leave (for better or worse), parents' need for care disappears (hopefully with as good an end as possible), estates are resolved, questions simplify.
TL;DR - The link between more money and less happiness sounds like coincidence. Maybe in your case you rushed into responsibilities you regret in hindsight, but I'm almost certain your choices wouldn't have stayed infinite even if you chose a different life.
I mean, if there's a loss to grieve, grieve. Your youth might be gone. But you didn't do it wrong.*
*I mean, mayyybe you did it wrong for you. That's for you to decide. But you'd lose your youth regardless of what you chose. And regardless of the money you made.
Heck, if you made no money back then, your options would have shrunk too. I can attest to that personally! :)