If your numbers are correct, SS + M&M + welfare = less than 800 billion or less than 20% of 4.7T tax revenue.
Plenty of room to cut needless spending before tackling "big 3" or defense(another approx 20% as related to tax revenue). Not saying they dont need addressed, just plenty of other expenditures that are just fukking stupid and could be cut immediately.
Cutting .gov workers/payroll may be a "small" number but it will also cut people who spend and all the ancillary costs of employing them. Those costs are probably much greater than their payroll.
Substantial revenue could be generated just selling off the real estate/infrastructure where those employees "work".
If you're unarmed, you are a victim.