If you think of an agent harness as a tool which you use to build your product, then I think you might be absolutely right. I don't see it being easy for a harness to ever build a product.

I actually think that the harnesses which do end up building products, the harness will be the product.

As an example, I have a harness which I have my entire team use consistently. The harness is designed for one thing: to get the results I get with less nuanced understanding of why I get it.

Mind you, most of my team members are non-technical, or at least would be considered non-technical, two years ago.

These days, I spend most of my time fine-tuning the harness. What that gives me is a team which is producing at 5x their capacity from three months ago, and I get easier to review, more robust pull requests that I have more confidence in merging.

It's still a far cry from automating the entire process. I still think humans need to give the outcomes to even the harnesses to produce the results.