More of a loophole maybe than hiding. Like perhaps being one big company in the US, but somehow being "separate" companies that "don't collaborate" in the EU?
There's other suggestions as to why, either to prevent experiments from tarnishing Google's brand, or to ensure Google's separate products can survive the eventual failure of the ad market.
The idea that they're "hiding" from the EU crackdown is ridiculous. They know perfectly well it doesn't work like that.