Negative freedoms are half a deal. All the old philosophers have a lot to teach us. We just don't have time to pay attention to them now.
Maybe Nietzsche said it well:
"Man does not strive for happiness; only the Englishman does that"
What did he mean?
> So if we aren't optimizing happiness, why not?
Because "happiness" isn't a thing. It's an idea we have about a thing that most of us are not courageous enough to name, let alone take for ourselves.