I'm intentionally including Berkshire, with full awareness of the difference between a conglomerate and eg Apple.

This is about economic power, reach, influence over daily life. Berkshire reaches into daily American life every bit as much as Amazon does. The difference is you don't see a lot of what Berkshire does.

Berkshire's energy position is massive. They operate one of the largest railroads. They operate one of the world's largest insurance businesses (or several of them if you view them seperately). They have huge influential stakes in everything from the largest banks to Coca Cola to Kraft Heinz. They're one of the largest owners of Apple.

I'd argue their influence on daily American life exceeds that of Amazon.

Does a single BH board have direct control over all of that influence on a daily basis, or is it broken up? However wrong many of its arguments are, the piece is arguing from a point of actual exercise of influence, in addition to theoretical holding of influence.