I am a progressive liberal, and damned proud of it. No, I don't believe government control can achieve utopia, but it can certainly improve the situation.
First of all, there are things that everyone needs, some desperately, that would never come about if we waited for private investment to accomplish them. Like vaccines. Like roads and bridges, education, police and fire protection. The reason government does those is that there's no other way to do them except wicked -socialism-.
Secondly, capitalism simply won't work without a certain amount of govt. regulation. Too much is as bad as too little, the art is in finding just the right level. But Republicans take the attitude that ANY amount of regulation is just evil. And so since Reagan we've had maybe a dozen major disasters brought about by imprudent deregulation. The S&L disaster, for instance. The housing meltdown. The stockbrokerage meltdown. The insurance meltdown. Enron, remember that one? We still have corporations Too Big To Fail, so this will inevitably happen again.
I can see you're a libertarian, not a conservative. Conservatives use 'liberal' to describe anyone they disagree with or anything they don't like. For libertarians, it's -statist-. Anyone who believes there even -should- be a state is a -statist-. 8^)