If there were a perfectly reliable, super easy to use jetpack: you would not be allowed to use it. Even if the technology were there, so are powerlines, helicopters, and other jetpack users.
Besides that, there are billions of dollars of security fences around government and other installations like power plants. I doubt they would let that be basically nullified, and would fight tooth and nail to prevent the sale of these, if they existed .
Less likely to prevent sale than just require adherence to FAA flight rules as already required for any other flying object, like drones. FAA both has all kinds of flight restrictions around many types of facilities, puts out all kinds of NOTAMs (Notice To Arimen) for temporary flight restrictions, and nearly anyone flying anything is required to check and follow these for every flight. Additionally, commercial drones have geofencing so they won't even fly within restricted areas.
If you fly your drone over restricted mil bases, you can expect a lot of enforcement to show up really fast, including weapons aimed at your drone. They'd have no problem enforcing the same kind of rules for a person flying over an area where deadly force is authorized for trespassers than they would for a trespasser on foot or vehicle, and you'd be a much easier target, and much larger audible signature.
I wouldn't worry that this concern will kill the industry.
Except for safety issues, all those issues exist with drones, and you're still allowed to fly drones. More likely is that certain areas would be blocked / limited.
It is fundementally different to have a camera above a military base and a person infiltrating it. Nobody dies when your drone hits a power line either.
Besides that, there are billions of dollars of security fences around government and other installations like power plants. I doubt they would let that be basically nullified, and would fight tooth and nail to prevent the sale of these, if they existed .