There's a bit of a circular argument here - even if we human always assign intrinsic value to ourselves and our kin, I don't see a clear argument that human capabilities will have external value to the economy at large.
If you "unwind" all the complexities in modern supply chains, there are always human people paying for something they want at the leaf nodes.
Take the food and clothing industries as obvious examples. In some AI singularity scenario where all humans are unemployed and dirt poor, does all the food and clothing produced by the automated factories just end up in big piles because we naked and starving people can't afford to buy them?
But we're clearly not there now, so I stand by my prediction for the medium future!
Corporations and governments have counted amongst their property entities that they did not grant equal rights to, sometimes whom they did not even consider to be people. Humans have been treated in the past much as livestock and guide dogs still are.