Not every problem faced by people in 1919 has been addressed by technology. Disease and old age still kill people. While it is true to say that many of the problems we face today will not be problems for people in 2100 we cannot know which problems will be fixed and which will be still intractable. Therefore, it is naive to assume that a solution for a specific problem will appear. Maybe it will but it is also possible that it won't.
True, but it's estimated that not long after mid-century we're going to experience a technological explosion with changes so vast and unthinkable it will make most pieces of science fiction ever written look like a joke:
https://en.wikipedia.org/wiki/Technological_singularityhttps://www.cnbc.com/2017/11/06/stephen-hawking-ai-could-be-worst-event-in-civilization.htmlImmortality may be likely. We may even become irrelevant as a species. Meanwhile we're worried about CO2 molecules.