That's pretty funny. Strictly speaking, there has to be more robots than people in the park at any time. Probably by a factor of 10-20 or so if you want people to feel like the real people tourists are a small minority. Implying each robot is earning about $2,000-4,000/day. Ignoring the fact that they get destroyed and other fixed costs, it would take years to pay these things off assuming they cost upwards of $10M each.