The world economy is dominated by people in governments who believe that printing money, burying it and paying people to dig it up again will increase the amount of trucks built and goods shipped. No amount of failure of this theory will be enough for it to be abandoned, because it has a certain amount of truthiness to it, and it excuses profligate and wasteful behaviour. Both these things are fun and buy votes. The…
That said, I do not think this is a case of a bad economist.
Economics theory is theory... theory that attempts to quantify societal behaviour, various cooperation dynamics, measurable output, etc. None of them know how to deal with various problems like "quality" & "technology" even though all economists admit they are pretty important. These theories usually have money playing a central role in some way). Anyway, they're theories about people acting together in big groups economics calls markets.
Political dynamics is another piece of the puzzle. So is every other meme in society. In some place homosexuals are allowed by society. In some places it is banned. Why now? Why not in 1750 or 2235? There are theories about how to quantify and predict here too, but obviously the ability of theories about such things are not up to the task of making consistent predictions.
Asimov's "psychohistory" is a fictional discipline which is basically economics, historical determinism, political science etc. The fictional twist is that these theories can make consistent predictions within very usable margins of error.