However, let's assume that they are valid objections. They certainly could be. After all, few would argue that the alternatives to capitalism are perfect, just that they are better. It's probably impossible to create *perfect* economic and political structures, and it's impossible to guarantee that a certain system will operate in ways that we desire, if only for the obvious reason that it's functioning hinges critically on the complex dynamics of society.
Having said that, imagine we reversed the situation. Imagine we were living in a socialist society and were theorizing about the possibility of changing to a capitalist society. Just think of all the criticisms one would have!
Point being, when people think about alternatives to capitalism I hope that they will remember to think about what they are comparing it to.