It would be no different from straight paying Google so they map the streets for instance.
It could be argued its a pragmatic choice to have the most impact on people’s life.
If the government then wants to work with commercial vendors of maps to integrate that data, then that is fine too. They can use the open data set just like anyone else, or the government could pay them to integrate that data if there is no intrinsic commercial interest in doing so.
So spending money to add roads to Google Maps is just stupid, because if you add them to OSM it's much faster and Google Maps will get them anyway.
Not only would attribution be required, but OSM does (for some use cases) have a share-alike clause. It could result in Google having to release their Google Maps data for OSM to use. So I'd be _really_ surprised if they did that, and I'd assume they'd be strict about making sure it's not imported.
If you have evidence, I'm sure the OSM community would be _very_ interested in hearing it.