They would need resources, and they would have to compete for those resources with the dominating manufacturer. If you own resources, why would you give them to the person who has nothing to offer in return? You won't.
So it will be a group of people who own resources, one guy who makes food and one guy who makes clothing. These are the only people who will get to eat.
Food grows right out of the ground. Water falls from the sky. One person is not going to own all the land in the world, nor all the water. Even if someone did, he wouldn't be able to police it all to prevent other people from living on it and growing their own food.
If in this theory though one person was able to make all the worlds food, they would would in turn employ the people so they would have something to give back for the food, it would be in the single food producers interest to put as many people to work as possible.
<sarcasm>As a result, all non-participants will die off, and those remaining will form a fully-functioning and harmonious society. The end result is the same: everyone who's left is happy.</sarcasm>
So it will be a group of people who own resources, one guy who makes food and one guy who makes clothing. These are the only people who will get to eat.