As others have pointed out, you should be more hesitant to call this a failure. You've learned a lot about your market, and you've also learned a lot about your vision, by exploring it "hands-on". Would you have gotten that if you'd instead spent 12 months developing your product before releasing it? Probably not. In short, it's best to err on the side of releasing too often than not often enough.
But the more important point is a clear demonstration that you can't replace a project manager with a motto. "Release early and often" is a good practice, but all practices need to be adapted and tailored to your specific project. You can't just follow them dumbly. A project manager's job is to understand the specific circumstances of your project, pick the right practices at the right stage so that your project goes as well as possible, then adapt and evolve those practices as the project goes along. No single practice is ever going to be always right.
As others have pointed out, you should be more hesitant to call this a failure. You've learned a lot about your market, and you've also learned a lot about your vision, by exploring it "hands-on". Would you have gotten that if you'd instead spent 12 months developing your product before releasing it? Probably not. In short, it's best to err on the side of releasing too often than not often enough.
But the more important point is a clear demonstration that you can't replace a project manager with a motto. "Release early and often" is a good practice, but all practices need to be adapted and tailored to your specific project. You can't just follow them dumbly. A project manager's job is to understand the specific circumstances of your project, pick the right practices at the right stage so that your project goes as well as possible, then adapt and evolve those practices as the project goes along. No single practice is ever going to be always right.