It's really quite easy to regulate many small competing entities. There are plenty of people ready to fill the role of IRS agent, and even the cost is relativel

It's really quite easy to regulate many small competing entities. There are plenty of people ready to fill the role of IRS agent, and even the cost is relatively trivial. What's practically impossible is regulating a few anticompetitive megacorporations. You can't regulate an entity that writes your nation's laws.