Maybe.
Try this on for size:
The people who were content (happy) living in mud huts eating bananas, bugs and beasts stayed put.
The people who weren't happy, the people who wanted more, left looking for greener pastures.
The genetically content were happy with their lot in the new territory stayed. Their siblings who who were genetically discontent kept moving, anywhere they lived wasn't quite right.
Not happy having to chase down game they domesticated animals. Not happy to range far and wide for a few nuts and berries, they invented agriculture. Not Happy with mud and wattle, they invented brick, and not happy with brick, they figured out how to hew stone.
Not happy having to make everything they needed they invented trade.
The rest is history.
Africans are a happy people, they sing and dance for everything.
The bane of progress is satisfaction.
Excellent point.
I have seen lines of argument like yours before, and I can see some truth in it. Basically, contentedness breeds laziness. I mean, if all you had to do to eat was walk out the door and pluck a fruit from the tree, why would you bother to invent agriculture?