Whenever I hear statements like this, I cannot help but think that the person making the statement has never done a week of work as "unskilled labour" themselves. (No offense intended.) Be it flipping burgers or building houses, there is improvisation both when it comes to high-level intelligence and in the ranges of motion the human limbs go through that make robots a complete non-starter.
Adding to that, a cheap robot arm that can lift as much as a four-year-old is $20k purchase price, plus another $20k for the controller/AI system, and probably $2k-$3k a year in maintenance. Figure four year depreciation when run 8 hours each day, you're looking at a yearly cost of $12k. That's compared to ~$15k for someone working full time on minimum wage. Take into account the huge process of switching your business over to robots, and it just doesn't look good.
Also, we don't need AI to take a customers order, you just need a touchscreen, or even just an app. The tech has been here for more than a decade. Why don't restaurants do this?