You can use anti-monopoly laws to do other things besides just breaking up companies. You can force them to not use their other entities to advantage themselves over competitors (promoting google services over others in search results). You can force interoperability and prevent shutting out competitors. You can prevent buying up new companies that compete with a google product. You could enforce a minim standard for consumer protection and codify rights to access for customers.

Many power companies have government enforced monopolies across the US. They also are heavily regulated and limited in what they can do to prevent them using their monopoly to extort, abuse, or neglect consumers.