If it wasn't for the courts and a decent de-facto "constitution" (collection of treaties really), governments would absolutely love to expand the amount of data

If it wasn't for the courts and a decent de-facto "constitution" (collection of treaties really), governments would absolutely love to expand the amount of data they (police, spy apparatus, etc.) have access to. That they also try to reduce the amount of data companies are allowed to save for themselves is tangential. The court case I linked is evidence of that. The German state wanted Telekom to save more data, but the telco refused and won in court.