I think the problem was that you mainly entered typically saturated (product) markets. All those ideas have been on the 101 "first product" lists to programmers

I think the problem was that you mainly entered typically saturated (product) markets. All those ideas have been on the 101 "first product" lists to programmers, for as long as you've been trying. And the fact that you worked alone(?) just makes things even more difficult. You have entrepreneurs in SF with networks and capital to launch products in mere months - hell, their marketing budget the first months would be more than your revenue the first x years. Point is, it's incredibly hard to compete against players like that, and if you have some easy / low-hanging fruit idea, there's a good chance you'll be playing against those. Remember to do your market and product research!