Your hypothesis seems to be that companies in low-tax countries have a higher growth rate than higher-tax countries in the same industries. If that were true, then companies in those countries would eventually dominate the world's market share. Instead, it's companies in higher tax countries that are the largest.

Governments often increase productivity. Try investing in a country with no laws, education, or infrastructure. They can also help make an economy more efficient by maximizing positive externalities and minimizing negative ones. Social benefits can also be beneficial economically as an externality. Companies don't have the incentive to keep someone from starving or to educate them from kindergarten, but having a larger, more educated work force certainly benefits the economy as a whole.