I don't believe it is. If we think of AI-maintained software as automated gardening / automated agriculture, the harness is all the machinery that can plow, sow, water, monitor, harvest, etc. There still has to be a human stewarding the overall ecosystem and tending the garden. The human is 'on top' of loop rather than 'in it' but I don't think a harness by itself can be a good steward of architecture.

Product org problems also is very context-dependent. Product orgs can work significantly different, in some orgs humans desire to be deep in the details, in other orgs the product folks are happy to let engineering drive the boat beyond a certain level of complexity. So one size harness can't necessarily fit all.