If tech giants such as Google cannot be broken up, then their services should be required to be compatible and all data exportable to competitors. See the EFFʼs “Competitive Compatibility” concept. Buy a movie off Google's YouTube but Google misbehaves? It must be exportable to a market competitor that you do support. Don't like how Google handles your email? You should be able to switch your email address to a competitor just like you can change phone companies without losing your phone number.

Basically, if the US Federal government cannot discipline monopolies by breaking them up directly, they should break up the moats and walled gardens the monopolies built to keep customers locked in to maintain their monopolies. See Chokepoint Capitalism by Rebecca Giblin and Cory Doctorow.