You are simply describing the fact that when we speak of growth of the GDP, we are averaging millions of things together. How else would you measure economic growth in a modern, diverse economy? That some sectors boom while others fade is well known, but we only care about the final aggregate. That final aggregate did well for most of the period from 1870 to 1970 (with the exception of the 1930s). But since 1970, that aggregate has done poorly