I think you're likely underestimating the resources it takes to make robotics work. They get better all the time, but they do so by a lot of blood sweat and tears. We haven't even managed to make them walk at all convincingly yet, it's a really tough problem. As messy as the virtual world can be, the real world is a lot messier. In the long run robots are almost certainly cheaper, in the short term though they are usually very expensive resource wise.