I did not argue the tools lowered the value of labour in aggregate - I merely said that they did not increase it. However, the effect on the individual and the group are different. If you have 10 people carrying boulders across the field, and you introduce a wheelbarrow, and now you have one person carrying the same amount of boulders across the field, the total aggregate value of labour has stayed the same. This particular person can certainly capture more of that aggregate value than they could have before, but the total value has not gone up. It’s also true that now you have lowered the cost of moving boulders across the field, so yes, there could be more demand for whatever it is you’re selling and that could mean that maybe you need two or three workers with wheelbarrows. but I think if you’re going to talk about the value of aggregate labor, you have to control for the amount of demand.