They don't stop spending. They spend trying to stay still or to do some extravagant scam that keeps the debt explosion of their bureaucracy from destroying them. The moral high energy (moral in sense of life well led) that let their success has long left the culture pilfered away in bread circuses and excesses of the ruling class. But they spend and spend like there is no tomorrow. They try to gobble everything external to prop the black hole core up. They more they do that the more overextended they are and the the more anti their true vigor and original good purpose.