Capitalism, as opposed to what economic model?
Capitalism (or more precisely, a competitive free market form of capitalism) has proved extremely successful at producing material wealth. Automobiles, clothing, toaster ovens, food, all of these are Nice Things to have. Command economies have consistently failed to produce material wealth at the scale of free market economies.
Capitalism has not been successful at producing other Nice Things, such as justice and equality, or a social safety net for people who happen to run into bad luck. If you have any kind of ethical compass and you care about these things, you should want other social structures like governments that are accountable to the people and so on.
Democracy and the welfare state aren't alternatives to capitalism, these are non-economic models. They can exist with or without capitalism.
Capitalism can't be the only organizing force in society, unless you're prepared to abandon morality. But if your stance is not to have capitalism at all, what economic model would you propose in its place?