No one is buying new homes and then turning around and selling them. They would lose their ass. They don't have a fixed price. Builders are selling each and every one for every dollar they can. Investors are typically buying distressed properties that the seller can't sell and the buyer can't buy in it's current state, repairing it and only then reselling it. If they didn't those sellers would just be stuck in those broken down homes forever.
There are some that do this, but having recently gone through home buying, a lot of them cover up problems with cheap finishes or don't fix things correctly, then charge a premium