The labor cost per unit of produce is pretty small. Even doubling wages for harvest and weeding labor wouldn't add significantly to the retail cost of produce. Additionally farming is heavily subsidized in the US. Modest wage increases could and would end up being covered by subsidies by getting them rolled into a Farm Bill.

You can bet that a farm that saved money weeding with robots wouldn't drop the price of produce reflecting their lower costs. Like prices if everything, it's more what the market will bear rather than some geometric relationship to labor/production costs.