Too Simple

We know that two factors are mainly responsible for slowing economic growth and causing poverty: taxes and government regulation.

If this is so, why not simply get rid of both?

This is clearly overly-simplistic, and not realistic. But this line of thought highlights the concept of a "necessary evil": we must have some amount of taxes, and some amount of government regulation, even though we know that they will cause harm. The best we can do is keep them to a minimum. To be practical, and not idealistic, we realize that we cannot create an economic utopia. There will be no perfect prosperity. But we can continually strive to make things better than they are. Although we won't arrive at perfection, we can persistently minimize taxes and government regulations, and thereby create the best chances for all citizens to enjoy a better income.