Nothing like tax inversions would exist if US tax law were not as stupid as it is and has been. When the cost of compliance is less than the total cost of avoidance companies and people pay their taxes.
From the point of view of those who make tax policy those laws work perfectly hand in hand with a massive increase in burdensome regulation.
Counterproductive tax law and massive increases in the regulatory burden is only stupid if you don't recognize what the goal of that approach is.