I don’t want to be pedantic, but it would be more apt to say: “Apple and Google, the US Steel and Standard Oil of our era” since Apple doesn’t own Google.
In response to a now deleted comment about if they constitute monopolies:
Hm, I'm sympathetic to where people are coming from. Treating Apple Apps as a distinct market from Android Apps doesn't feel technically true, but I think it's more then true enough.
More generally I think people have a sense of what fair play is and how large companies shouldn't be as free to throw their weight around, laws be dammed. And that whole feeling gets lumped under monopoly.