You're not alone. I'm 25 and have worked on roughly 5 major projects, and thus far all have failed due to execution; sometimes failing because of me, sometimes failing because of other people. Then there are all the small things, some of which succeeded but I didn't care for.
Being smart and being lucky aren't something you need to worry about. Being better tomorrow than you are today should be the goal. Even if it's just a small thing.
Ask yourself what you want in the next 5 years, and focus on that. It sounds like you want to focus on relationships and travel. Focus less on the ideas and the business stuff, those don't matter in the long run. Focus on life.
Today, I walked into work knowing I was going to quit, because I don't see the success. I failed at that, because I know the idea is good and I like the people, and for me to cut the cord early would fuck everyone else at the moment. I'm making a decision that means I'm unhappy for the moment, but I'm doing it for other people's safety.
I'm also suffering from the issue of having left a place I love and everyone I care for, for a place I don't fit in and can't connect with anyone. My social life is dead and it's not something I've been able to change in the valley.
I'm thinking about leaving tech, as a profession, because professionally it turns everything I love into a thing to loath. And going back to the slower pace of living, without fear of failure or success, just living intentionally and taking every day and every moment for what it is.