"Company XYZ already does this" isn't negative. It confirms that there's at least some market for the product. Don't let this dissuade you, and don't assume that your potential customers know about Company XYZ—just get working!
"Nobody is going to pay for this" is meaningless from someone who just learned about your product, who isn't in the demographic for it. I think it's ridiculous that people would be willing to spend thousands of dollars for a watch that spends 95% of its life WITHOUT the time on it's face. That doesn't mean it's going to fail—it just means that I'm not the market/demographic—yet.
Just keep doing what you're doing, if you have the stomach for it. If it takes 100 failures to get one success, focus on that success being only 100 failures away.
Really though, once you have a success, it'll starts to make more sense—I promise.