Except that we didn't have that problem before the Bush tax cuts. I understand that conservatives keep telling you this. But to quote Wikipedia, "Citation Needed". When adjusted for population growth, inflation, and economic growth, we are spending the same amount on non-discretionary non-defense as we did twenty years ago. Get rid of those tax cuts and wind down defense spending to pre-war levels, and we do have enough money.
Yes. You see, over time, both the population and economy of a country grows. In order to continue to provide basic government services at the same rate, the amount of spending must go up. If you reduce the amount on each Social Security check going out, this is a cut. The total outgoing amount for Social Security will continue to go up, almost no matter how severe the cuts are, because more people retire every day. Similarly, tax revenues continue to increase over time for the exact same reasons. Increase taxes, tax revenues go up. Cut taxes, tax revenues go up. Leave taxes alone, tax revenues go up. Same thing but from the other side.
We add two million people to the workforce every year. In short, an actual net decrease in spending is practically impossible unless both population and economic growth is near zero.