That happiness does not necessarily mean that leadership is benevolent or good, that it could be just as evil as the leaders we have today. A slave owner who treats his slaves well, keeps them happy is still a slave owner, and the people are still slaves, despite being happy.
Someone who is ignorant of personal freedom may well be happy, and so fulfil your objective but I wouldn't say that's a good life.
Yeah, well none of this is really to do with the main thrust of this thread. You're bringing into the picture imaginary situations where there is no need to. Either we get leaders exploiting our fears and misery, or we get leaders responding to our happiness in different ways. They need our votes. If we're all happy, and we vote them in and they go on their crime spree, then they're not reflecting our will, and we will evict them from office. They will learn fast.
Instead they have at their disposal the tools to downpress us with fear, debt, and marketing. If we resisted, then the ball would suddenly be in our court, to put it in tennis terms.
