Obviously not every trader wins. In fact, most traders lose.
For every Trade there is a person Buying and a Person Selling. If the price goes higher, the buyer and the broker make money. If the price goes low, the seller and the broker make money.
For every buyer, there must be a seller. So it is impossible for Everyone to be buying. Who are they buying from? (a seller).
Now, sometimes the Broker might be the seller (these are Brokers that have a Dealing Desk). In essence, they buy when you sell and sell when you buy.
Eg: Suppose they have people wanting to buy 10 lots. Then they have People wanting to Sell 6 Lots. Well, they will pair the 6 sellers, with 6 buyers, then they will sell off 6 lots to the remaining buyers. They will either keep this or they will pass it along to a liquidity provider.
In the end though, there is always a seller for every buyer, and if the price goes up, those sellers lose money. Whether they are average Joe’s like you and me, a Dealing Desk like Forex.com, or big time investers / banks.