Yes. And they’re already here. Next question.
“Yes. And they’re already here.”
100% true.
There are simple countermeasures to employ.
The drones are light and the explosive payload light. A simple hangar will go a long way. Chain-link cages around (and over) things like fuel storage systems, too. These are not expensive and quickly built.
All you need is a couple of meters of air between the drone and the target to protect against serious damage.
Even better are sand-filled hangars utilized in Israel. (Sand is placed between two layers of tin). This protects against much more serious weaponry. Do this as a follow-on.
Then add all your expensive and cool anti-drone technology, while also hunting for bad guys.
And finally, start building tougher infrastructure with redundancy in your system, especially utilities.
Get rid of nifty computer controlled equipment that can be hacked. As handy as it is, it is vulnerable.