The private sector has indeed been the source of much innovation that has led to improvements in standards of living. However the problem with relying solely on the private sector for social welfare, is that it can only improve the lives of those who can pay for it! It may well be the case that healthcare is better under the private sector, but if only the top 60% (say) of the country can afford it, there is a big problem! Moreover, as has already been mentioned, there is often insufficient financial incentive for the private sector to invest in certain areas, like pharmaceutical development or green energy research. Here, the government must step in and in the interest of public welfare provide the investment needed.  High level-taxation on wealthy individuals may be hard on them, but ultimately is desirable. Ethically speaking, we need to balance the harm of a millionaire losing a small portion of his or her wealth, with the enormous social good that can arise if that wealth was spent on social welfare programs. An extent of “redistribution” of wealth is thus fair and just.