Marco Gutierrez, founder of Latinos for Trump, warned darkly this month that Hispanic immigration would lead to "taco trucks on every corner." Yet, in truth, the factors that led to an explosion of taco trucks are reversing.

A recent study by the Pew Research Center showed that the growth of the Hispanic population in the U.S. is slowing drastically. Since 2010, it has fallen to a 2.4 percent annual rate, down from 2.8 percent between 2007 and 2014; 4.4 percent between 2000 and 2007, and a high of 5.8 percent in the 1990s. The overall U.S. population growth rate is a little less than 1 percent.

The decline appears even more stark if you dig into the numbers. Net immigration from Mexico has been negative since the recession, and Hispanic population growth is increasingly due to U.S.-born babies. And the birthrates of Hispanic mothers are collapsing.

Data from the Centers for Disease Control show that between 1990 and 2014, births per 1,000 Hispanic women ages 15-44 have fallen from 107.7 to 72.1.

Lower population growth means less geographic dispersion. Georgia, one of the states with the fastest-growing Hispanic populations in the 2000s, is a great example. The Atlanta Regional Commission points out that although the overall Hispanic population in the 20-county Atlanta area grew by 60,000 from 2010 to 2015, the population of Hispanics ages 20-34 fell by 26,000. As the great Hispanic immigration wave recedes, growth in this demographic may increasingly be clustered in places such as Texas, California and the Southwest.

Pretty soon, the only place to get a taco in Atlanta will be at Taco Bell.

As fewer Hispanics in the U.S. are foreign-born, the socioeconomic status of this group is changing. Teen birthrates are falling. Educational attainment is increasing. As they become more Americanized, their cultural tastes are changing, too. Univision, struggling with sagging ratings, is looking to shake up its programming to appeal more to American-born millennials.

So what drove the great taco-truck boom in the U.S. (apart from the fact that tacos are delicious)? It was the explosion in the less-educated Hispanic workforce from the 1980s to the 2000s. With Hispanic population growth now in decline, higher educational attainment and a tight service labor market, supply dynamics argue for a taco-truck bust. Much as demographics drove the rise and fall of the Jewish deli, the twilight of the taco-truck era may be upon us.

Conor Sen is a portfolio manager for New River Investments in Atlanta.