Well, in an ideal world, people pay taxes in exchange for public service from the government. Most social welfare needs to run on a large scale in order to lower its cost to a feasible level. But you are right, if enough armed people refused to pay and told the government to go fuck itself there is nothing the government could do. I guess the problem is whether the government established a trustworthy system to build infrastructure that people enjoy and feel like their payment to the government is worth every penny.