The conglomerate was supposed to be dead, a relic of a bygone era of corporate America. Investors, we have been repeatedly told, want smaller, nimbler, more focused companies.

And yet there is Amazon.

Just when it seemed that sprawling empire building had gone out of vogue — eulogies were written last week for General Electric after Jeffrey Immelt, its chief executive, retired under pressure from shareholders — Amazon announced that it was buying Whole Foods for $13.4 billion.

The deal will put Amazon in the brick-and-mortar grocery store business, which will exist alongside an ever-increasing bevy of disparate interests: the selling of everything from electronics to toothpaste online; payments and credit; cloud computing; production and distribution of movies and television programming; book publishing; shipping and logistics operations; and on and on.

It is actually a myth that conglomerates disappeared. They are now just dressed up with a bit of Silicon Valley flair, and dress down in the boardroom, with chief executives who wear sneakers.