In terms of casualties, most are inflicted by drones such as the MQ-1 Predator. Drones are very effective for striking targets because you can put a large number of them in the air over an area for long periods of time. The personnel manning them can take shifts, making them constantly aware and not nearly as tired. If an area needs to be hit by a strike, a drone can be nearby to move to the target, because they are much cheaper to keep in the air. You don't need a manned vehicle to hit a nearly defenseless ground target. You just don't. But the enemies we're striking are not a first world military. They're a bunch of guerillas who have very limited technology at their disposal. A military that has the capability to hack or jam our drones will not do so today because we are not at war with them, and if they did attempt to do such a thing, it could be perceived as an act of war. I imagine though that we are developing anti-drone technologies that have the capability to stop our own drones, and hopefully those of other militaries. If the Russians tried to use drones against us, we'd probably make all efforts to jam them, just as they would against us. Militaries are constantly testing these technologies in case they are needed. In terms of whether a UAS can be built to withstand jamming or hacking -- I have no idea personally, as I don't know much about these specific technologies. I do know, though, that any computer system is vulnerable to exploitation, and any piece of hardware that is designed to listen for an electronic signal can be inundated with signals designed to prevent a real signal from getting through (jamming). These are definitely weaknesses with using UASes. They don't make the technology worthless, they just define the areas in which the technologies can be used. I'm not saying that the US military is using them incorrectly, I'm just saying that the limitations of the technology prevent them from being used in many circumstances, and make them less advantageous than using more conventional technologies. Going back to the OP, the human body is a machine, just like any computer (as @zoupskim pointed out). An organic "super soldier" using performance-enhancing drugs could do very well against a mechanical "super soldier" using machinery instead of muscles. Both have pros and cons, so are viable options for future militaries.
Interesting, Although you must think about the drug dealers. The moment the learn of this device I can tell you they will be either A) Finding out how to make a drug that is resistant to the machine, or B ) Use the machine as a way to get a new drug into the body (basically using your anti-drug machine against you) Also if the military would want to use it I wouldn't go with a generic drug of todays world but would make up my own after LENGTHY research about the different kinds of drugs. If you want super soldiers I would start my research on PCP and go from there.
