Because the people in charge of deciding which work should be done have decided that we should spend every waking hour making them more powerful. Next!
We're still working this hard because we, as a group, want to. It is as simple as that.
Next!
We could just get rid of any inefficency.
Capitalism is driving our current economy, it doesn't has to.
There is no real reason why we couldn't decide tomorrow that every car is electric and depending on some factor you can just request a car.
Planet earth has resources x, the only question is for what we use it and how we distribute it.
But no if i want to be self sufficient (100%) i can't do this.
If i want to exit capitalism and build up a country not defined by it, i can't either.
If i kill bad leaders, i will be thrown in prison.