Wikipedia's text content is licensed under CC-BY-SA, which means that if Google isn't giving attribution somewhere then they would be in violation of the license.

Google gives attribution when text content is used.

For simple bibliographical information like who someone’s spouses is, it is not copyrightable, and no attribution is needed.

Facts may not be copyrightable, but by academic standards they should still be sourced. Google doesn't derive shareholder value from training people to seek primary sources, though.