[mswen]

In many ways you are in an enviable position. You can take pride in the fact that you worked hard (at something you apparently didn't like)but you worked hard enough and competently enough that you got paid really well. Second you can take a healthy pride in the fact that you were wise enough that you lived on less than you were making and built up investments such that you could retire on a modest income at 31. Relatively few people achieve that level of income and even fewer exercise that kind of discipline.

But you now desire significance and the potential for even greater financial success. Great, get started and quit worrying about whether you will succeed. As others have pointed out if History or English majors can teach themselves the skills needed to succeed in web or mobile development there is no reason to imagine that you will fail to acquire the skills that you need.

Quit worrying about competing for a "job" and use your investment income as an extended start-up runway.

As you start developing an idea, go learn the specific technology needed to develop that prototype. If it starts to get traction great, you might have a hit on your hands and retain all the equity. If it doesn't get traction, at least you learned a new technology. Rinse and repeat. Since you have basic income covered, I would focus on the significance side of the equation. Do projects that you care about.

If you eventually tire of trying to build your own ideas, find a non-profit whose mission you believe in. Use your newly developed skills to work for them and help make something good happen in the world. They probably won't be able to pay you all that well, but you have basic income covered.