I read your opinion well :)
As you wrote, glass tumblers should be used at least 15 times, plastic tumblers at least 17 times and ceramic tumblers at least 39 times to protect the environment, and  tumblers made to replace disposable cups also emit much more greenhouse gases than disposable cups in all processes. However, I think we use tumblers more than enough to at least protect the environment. Assuming that we only drink three cups of water a day, we've used enough tumblers to protect the environment in about two weeks. In addition, the process of manufacturing tumblers produces more greenhouse gases than disposable cups, but I think tumblers can be reused and consequently will benefit the environment without ever having to use tumblers for life. Thank you for reading!