Some have been shot down via shotguns in Ukraine, there are some pretty good videos of it. The issue is that even if successful, the information feed has already gone back, so location, troop assets, etc are all known. Taking it down saves a life, but the info it acquires is also already sent back to be acted upon. What a lot of people don't seem to understand about these videos showing people being blown up is that they are taken by another drone that is observing. If you watch the videos the troops on the ground are focusing fire and all of their attention on that single drone. I'll leave it at that.
It isn't just technology, but its also tactics that are going to have to evolve. The world has changed and it really is no joke.