1. The simplest answer is that federal spending has always been out of control.

2. This assumes a 100% effective government. If it's only 70% effective, you can cut spending by 30% without affecting the noble goals you list.

3. This is the Luigi argument. Get rid of health insurance and we'll all be happy! What exactly to replace it with is TBD.

4. The main argument against high corporate taxes is that it leads to companies moving to countries with lower taxes. The US still has higher such taxes than most and suffers from that, but the optics of lowering further are too bad, so we live with it.