In Madison, they still struggle to ­accept that it's really happening. On a not-yet-specified day before the end of March, a Kraft Heinz ­employee will turn off the lights in the sprawling Oscar Mayer plant, and for the first time in 98 years, no one will be coming back to work.

The facility was once the city's largest employer, with over 4,000 workers transforming hogs, 900 an hour, into Oscar Mayer hot dogs, bacon, sliced ham, and more. Employment was down to about 1,000 when Kraft Heinz announced in 2015 that it would close the plant, and recently the workers had dwindled to about 400; the products still being made include an item called liver cheese, which few consumers under age 80 are clamoring for.  [...]

The 3G management model that Buffett so admires is worth a close look because it's on track to eat the food industry. At its heart is meritocracy, broadly defined. Every employee must justify his existence every day. That's great news for the very best performers; they are promoted with speed that's unheard-of in lumbering old food companies. Kraft Heinz CEO Ber­nardo Hees, for example, first became a CEO in 2005 at a company called All America Latina Logistica, owned by a 3G predecessor. He was then made CEO of Burger King, a 3G holding since 2010. He moved up to be CEO of Heinz in 2013 and now of Kraft Heinz. He's only 46.

Underperformers get fired with the same alacrity. Budgeted costs also are evaluated unsparingly every year, or more often, and are eliminated if they're no longer judged worth incurring. After all, Hees (pronounced "Hess") and other top executives are 3G partners. Their own money is tied up in each venture, and they can't afford to be sentimental about it.

Which brings us back to the Oscar Mayer plant in Madison. The truth is, that plant should have been closed long ago, and everybody knew it. "The Madison plant was a terrible plant," says John Ruff, a retired Kraft executive who spent much of his career in food-processing plants worldwide. "It had good people, but it was an old plant that had been added to over the years. It was never meant to be run as it was being run. Closing it was probably the right thing to do." So why hadn't Kraft closed it long before 3G came along? The reason is a classic problem for big, old businesses: People loved that plant. It was a treasured part of the company's history. But not to 3G. "[Kraft] had trouble making tough choices," says Credit Suisse analyst Robert Moskow. "3G has forced them to make tough choices, like closing the Oscar Mayer facility. It was very emotional." Ruff agrees: "3G got rid of a lot of remaining emotional ties."

Now project that philosophy across a $26 billion company. Step 1 in the 3G management model is a wholesale replacement of the top team and a blitzkrieg of cost cutting. At Heinz, 3G cashiered 11 of the top 12 executives in one day (as this publication chronicled in a 2013 story headlined "Squeezing Heinz"). When Heinz bought Kraft, 10 top executives were quickly dismissed. Of Kraft Heinz's top 10 leaders today, eight are Brazilians from 3G who know the playbook. "If you don't speak Portuguese, you're at a bit of a disadvantage," says a former Heinz director.