I went to a symposium on assessing the value and future investment in robotic surgery a few years ago. Figuring out if it is cheaper or not, than regular surgery is surprisingly difficult.
For simple procedures, you might ask junior staff to do it with a robot, to get them training on the robot - compared to sending staff of to seminars, this is actually cheap, even though it is more expensive than regular surgery.
You might also ask junior doctors to do a slower, more expensive job on a robot to get their performance up to the same level as expert staff.
And even experienced surgeons might opt for using the somewhat scarce resource only for difficult cases. So you might end up with the same surgeon, on the same type of procedure, having a worse track record on the robot, because the severity of each case is not recorded in the statistic!
For simple procedures, you might ask junior staff to do it with a robot, to get them training on the robot - compared to sending staff of to seminars, this is actually cheap, even though it is more expensive than regular surgery.
You might also ask junior doctors to do a slower, more expensive job on a robot to get their performance up to the same level as expert staff.
And even experienced surgeons might opt for using the somewhat scarce resource only for difficult cases. So you might end up with the same surgeon, on the same type of procedure, having a worse track record on the robot, because the severity of each case is not recorded in the statistic!