Given the above assumptions that seems doable to me. 2 years of working nearly 24/7 with virtually no costs(compared to wages/benefits) would more than pay for itself. But I don't think the above assumptions are necessarily correct, that sounds a bit too cheap to me.
It may be doable, I am not trying to be overly negative. It's just that I probably wouldn't target minimum wage workers with this robot.
Also you say "no costs" but do you honestly think these would be maintenance free? There would probably be a fairly significant cost to keep a fleet of these robots running as they are incredibly complex as compared to say an amazon warehouse robot.
