Guess what? There are actually ten million millionaires in the US, and we've just cut the deficit by US$10 million. You care about the deficit, right? If so, you should be intrigued by my idea of reducing the deficit with no pain whatsoever.
Now, the other extreme is obviously bad. If we took most of what rich people earn, indeed they'll find some way to avoid it, perhaps by moving elsewhere. But surely there's some small amount that we could increase their taxes to help reduce the deficit, without them even really noticing? We can reduce the deficit by a billion dollars by taxing each millionaire a mere US$100 more. That's a bit over US$8 a month, not even three fancy coffees. Do you really think that would stop them from "creating jobs"?
The opposite in the political spectrum is true: if we paid a dollar less per recipient of Social Security, we'd save a good chunk of money (about US$60 million). If we cut too much, they'll be endangered.
Now, you might say that a billion here or there isn't a lot of money, compared to the trillions in debt. That's right, and the debt needs to be addressed by big (and probably painful) solutions, but why not cut a billion here or there anyway?
So let's stop saying that taxes absolutely cannot be raised, and benefits absolutely cannot be reduced, and instead find a balance that shares the burden like a united country should.