Your thing likely has much more novelty than you think it does.

For example, stitching together established components in a novel combination is in itself novel.

It might feel like the thing you're applying a system to is 99% like what it's been applied to before, but perhaps it's more like 80%.

When you feel like you're 80% of the way done, you're likely only 20% of the way done.

The amount of novelty to navigate ramps up significantly in that last bit between the idea and deploying it successfully in the real world.

The benefit of using robust, "lindy" solutions is that the real world has wrung all of the unknown unknowns out of it.