ChatGPT and Claude are programs that are not publicly available. They run on privately owned, powerful computers (servers), and your only access to them is through those servers. For better-performing models, you have to pay a subscription. They also cost a lot for the companies to run because they waste a lot of energy.
Chinese AIs like deepseek or qwen or glm, on the other hand, are very efficient while performing pretty well, which means they're cheaper to run. At the same time, they're publicly available, so anyone can download the models and run them on their own computer.