Google still catching up for more than a month. Amazon still doesn't have anything comparable, but definitely needs and wants it. So it doesn't looks like it's easy to replicate. Besides, it's not a finished product. It's a service in continuous development. For how long OpenAI will be able to stay ahead of competitors is yet to be seen. They are trying to create a secondary market of resellers. This may keep them in business for long time if they are just "good enough".