It's more efficient now than it used to be - by which I mean the total taken by HFTs is lower than what people used to pay in spreads and commisions. Price discovery is better (you get closer to a fair price if you trade) and spreads are lower. The whole industry that used to prey on spreads and ignorance of retail investors is gone. What not to like about HFT?

You think you could do better by having a planned economy, with your eminence deciding what's a waste and what is not? And why should I believe you it'd end up differently than North Korea or Cuba?

Or you'd somehow manage to take what you think are all the good parts of western societies while outlawing what's wasteful and we'd have an utopia?