ISTANBUL — For 17 years, President Recep Tayyip Erdogan won elections by offering voters a vision of restoring the glories of Turkey’s Ottoman past. He extended his country’s influence with increased trade and military deployments, and he raised living standards with years of unbroken economic growth.

But after a failed 2016 coup, Mr. Erdogan embarked on a sweeping crackdown. Last year, the economy wobbled and the lira plunged soon after he won re-election with even greater powers. As cronyism and authoritarianism seep deeper into his administration, Turks are voting differently — this time with their feet.

They are leaving the country in droves and taking talent and capital with them in a way that indicates a broad and alarming loss of confidence in Mr. Erdogan’s vision, according to government statistics and analysts.

In the last two to three years, not only have students and academics fled the country, but also entrepreneurs, businesspeople, and thousands of wealthy individuals who are selling everything and moving their families and their money abroad.