In physics, chemistry, geology, anthropology and a number of other sciences the risks of fraud and various forms of cheating are great and the penalties for getting caught are drastic - loss of your career. For the most part, nobody else has a big stake in your opinions. Medicine has more cheating and the penalties, overall, are less. Vast fortunes hang on promising new treatments, and big funds flow toward projects that seem promising and if you lose your job at a research U, you can still go into clinical practice.
Economics is different, especially from the first group of sciences. The most efficient and common way to get rich is getting a government to put a money spigot in your pocket, so there is a big incentive for the rich and would be rich to influence where those money spigots get placed. Consequently, influencing government economic (and other) policies is a high payoff activity. If you get to be a high profile economist, those funds can flow to you, provided your opinions please somebody with a big stake in the economic outcome.
Pablo Escobar would never have become rich if the US hadn't had a war on drugs. Bill Gates is rich because the government grants him some exclusive licences and protects them. Sheldon Adelson is fabulously wealthy partly because China prohibits gambling except in his casinos in Macao. The history of some of the first fortunes in the US is an instructive one. During the revolution, the Continental Army and it's suppliers were paid largely in script - promises of payment upon sucess of the revolution. After that revolution, the government couldn't get around to paying.
When the Constitution was adopted, and Alexander Hamilton became Secretary of the Treasury, the script holders had been unpaid for many years, and Hamilton's banker friends bought up the script for ten cents on the dollar, or less. Hamilton then insisted that the new government pay its debts, and they became rich.
The fortunes of many of the Russian oligarchs were acquired rather similarly. Guess who advised the post Communist government on how to privatize the old socialist industries.
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