winner-take-all

Of or pertaining to a contest, election, or other competition in which only the winner is rewarded and none of the losers receive anything.

You need luck in poker tournaments, because in the nature of this winner-take-all style of play, there will be several occasions when you cannot avoid putting all your money in the pot.

Under winner-take-all elections, many minority candidates find it nearly impossible to win.

Of a market in which a product or service that is only slightly better than its competitors receives a disproportionately large share of revenue.

Of a neural network model: organized so that neurons in a layer compete with each other for activation.