To make a prediction about the future economy, you really need to make a prediction about how technology will impact the future.. I am not certain what knowledge your high school econ teacher has about AI and other cutting edge technologies, but I am guessing it is limited. The same can be said for most posters in this board.
If you want to get a sense of what things may be like in 20 years, read the new book AI 2041. Although no one can predict the future and I am certain much of what this book says will be wrong, the author is a leading AI venture capital investor and probably has better insights than most high school teachers or running website posters.
But the key is that no one knows, not even experts, so you should attempt to get a variety of opinions from technology experts, economists who understand technology, etc.