When is the time to fail?

I was thinking lately about failure and declaring a SaaS/side project as failed. Many successful solopreneur/indie hackers like to boast how they “made 27 products that failed before finding this one that succeeded”.

However, observing other founders/builders who share their journey on social media, I came to a conclusion that there are only two components to a successful project: consistency and luck.

Consistency gives you two things. The first one is skills and knowledge. The more you stay “in game” of building, the more you learn about building a business and the industry. The second is authority. This could be a social following because people are interested in your journey, which gives you an audience that you can then leverage to sell your product to. Or this could be a real authority because you stayed so long in the industry that people now know you.

Luck, is well, it's luck. No matter how many people will claim to “hack the algorithm”, nobody really knows why your ads are shown, or how SEO really works. And it’s enough to fall on a customer who will see your ad, or click your link on Google, who will become so passionate about your product that he will tell his friends, which creates a chain reaction and spreads the word further. Or a social media post that can suddenly become viral, which will generate traffic to your product. This is luck. We can't control the outcome of luck. We can influence its presence. I can create 500 pages for SEO purposes, but I can't control whether Google will actually index them.

I can confidently say that this formula applies to the vast majority of products I observed in the past 8 or so months that I became active in the indie hacking community. Truly unique products rarely exist, and these that “succeed”, are some combination of consistency and luck.

Having said that, this means that every product has the potential to become successful. With enough consistency, and some occasional luck, failing a project makes no sense. And this raises the question of when and if you should fail a product?
I've been working on JustFax (info in my profile) for about 3 months now. It's far from becoming successful. I've learned a lot about building products as well as the telecom industry. And yet, sometimes, I have the urge to abandon it and pivot to a new product (luckily, I have an endless list of ideas). But I always come back to the above formula: success = consistency + luck. Assuming it's truly correct, it makes no sense to abandon a project. I have dozens of strategies I haven't tried yet, which means that one of them could be the luck I need.

So I ask you: when is the time to fail a project and move on to the next one?